JPH0962885A - Data recording device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record a characteristic value and discrimination data showing whether data is normally written or not on a vehicle data recording device recording and preserving the characteristic value showing the state of a vehicle into a non-volatile memory under a prescribed condition. SOLUTION: Acceleration operating on the vehicle is recorded into RAM at any times. When deceleration exceeding a prescribed level operates on the vehicle, acceleration data in RAM is recorded into EEPROM. At the time of starting writing data, start data '0A' is recorded into a writing flag area of EEPROM (step 202). All acceleration data in RAM are written into EEPROM (steps 204-214), termination data 'A0' is overwritten into the writing flag area (step 216).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording device for a vehicle, and more particularly, to a vehicle before and after a predetermined situation occurs by recording a characteristic value representing the behavior of the vehicle in a non-volatile memory under the predetermined situation. The present invention relates to a vehicle data recording device for storing data regarding behavior.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 1-164464
As disclosed in Japanese Patent Publication No. 9, a device is known in which a characteristic value representing a running state of a vehicle is recorded in a non-volatile memory to save data on vehicle behavior under a predetermined situation. The device disclosed in the above publication is a data recording device for storing acceleration data before and after an airbag system mounted on a vehicle is activated.

In the above apparatus, the output signal (hereinafter referred to as G signal) of the acceleration sensor mounted on the vehicle is recorded in the volatile memory (RAM) in the electronic control unit at any time. When an acceleration exceeding a predetermined value is applied to the vehicle, the process of recording the G signal in the RAM for a predetermined period is continued thereafter, and at the same time, the acceleration data recorded in the RAM, that is, the vehicle. Acceleration data for a predetermined period before and after an acceleration exceeding a predetermined value acts is written in a non-volatile memory (EEPROM).

Writing data to a non-volatile memory requires a longer time than writing data to a volatile memory. Therefore, the G signal cannot be directly written to the nonvolatile memory after the acceleration exceeding the predetermined value is detected. On the other hand, like the conventional device,
If the G signal is once recorded in the volatile memory and then the data in the volatile memory is written in the non-volatile memory, the acceleration data over a predetermined period can be stored in the non-volatile memory without being limited by time constraints. Can be stored in the memory.

Further, the acceleration data written in the non-volatile memory is not erased even when the power supply to the electronic control unit is cut off. For this reason,
According to the above-mentioned conventional device, when acceleration exceeding a predetermined value is applied to the vehicle, even if the power supply to the electronic control unit is cut off due to the influence of the acceleration, the acceleration data over the predetermined period is ex-posted. It can be read from non-volatile memory. Therefore, if the above-mentioned conventional device is mounted on a vehicle, the magnitude of the acceleration acting on the vehicle can be accurately analyzed afterwards.

[0006]

By the way, in a situation where an unreasonably large acceleration is applied to the vehicle, power is supplied to the electronic control unit immediately after the acceleration is applied due to the damage of the vehicle-mounted battery or the like. May be cut off. On the other hand, in order to write the data in the volatile memory to the non-volatile memory, some time is required as described above. Therefore, depending on the state of the vehicle when acceleration exceeding a predetermined value is applied, the operation of the electronic control unit may be stopped before the writing of data to the nonvolatile memory is completed.

The data in the non-volatile memory is not always erased every time recording is performed. Therefore, acceleration data may be already written in the nonvolatile memory at the time when the acceleration exceeding the predetermined value acts on the vehicle and the writing of the data to the nonvolatile memory is started.

The above-mentioned conventional apparatus has a configuration in which only acceleration data is recorded in the non-volatile memory when an acceleration exceeding a predetermined value acts on the vehicle. For this reason, when the acceleration data is already written in the non-volatile memory, the acceleration data writing is started, and then the electric power supply to the electronic control unit is cut off early. Without any distinction, the acceleration data written this time and the acceleration data written by the process before the previous time coexist inside.

If a plurality of acceleration data are mixed and recorded in the non-volatile memory, accurate acceleration analysis may not be possible even if the data is read out afterwards. In this sense, when the old and new acceleration data are mixedly recorded in the non-volatile positive memory, the conventional device may not be able to perform accurate acceleration analysis depending on the contents of the old and new data. You have a problem.

The present invention has been made in view of the above points, and the determination data indicating whether or not the data writing to the non-volatile memory is normally performed, together with the characteristic value indicating the state of the vehicle. It is an object of the present invention to provide a vehicle data recording device that solves the above problems by recording in a nonvolatile memory.

[0011]

The above-mentioned object is defined in claim 1.
In addition to storing the characteristic value representing the state of the vehicle in the volatile memory, the data in the volatile memory is written to the non-volatile memory under predetermined conditions to save the data. In the recording device, under the predetermined condition, the data writing unit that writes the data in the volatile memory to the nonvolatile memory, and the operation of the data writing unit is stopped during the data writing to the nonvolatile memory. The discrimination data corresponding to whether or not
This is achieved by a vehicle data recording device, comprising: an operating state recording unit that writes the data in the nonvolatile memory.

In the present invention, when a predetermined situation is detected, the data writing means writes the characteristic value recorded in the volatile memory into the non-volatile memory. Further, in the non-volatile memory, the operation state recording unit records the determination data indicating the operation state of the data writing unit. In this case, the discrimination data indicates whether the data recorded in the non-volatile memory is accurate data.

Further, as described in claim 2, the above-mentioned object is, in the vehicle data recording apparatus according to claim 1, the operation state recording means starts writing data to the nonvolatile memory. Start data recording means for recording start data in the non-volatile memory when writing, and end data recording means for recording end data in the non-volatile memory when writing of data to the non-volatile memory is completed It is also achieved by a vehicle data recording device including:

In the present invention, the start data recording means records the start data in the non-volatile memory when the writing of the data to the non-volatile memory is started. Also,
The end data recording means records the end data in the non-volatile memory when the writing of the data to the non-volatile memory is completed. If the data writing is stopped before the data writing to the non-volatile memory is finished, the start data is recorded in the non-volatile memory, and when the data writing is normally completed, the end data is written in the non-volatile memory. Will be recorded. As described above, which of the start data and the end data is recorded last corresponds to whether or not the data writing is properly ended.

Further, the above object is, as described in claim 3, in the vehicle data recording apparatus according to claim 1, wherein the operating state recording means is a state of progress of writing data into the nonvolatile memory. The progress data corresponding to
It is also achieved by a vehicle data recording device including a progress data recording unit for recording in the nonvolatile memory.

In the present invention, the progress data recording means, when the data is written in the non-volatile memory, writes the progress data corresponding to the progress state in the non-volatile memory. The progress data will indicate up to what point in time the writing of data to the non-volatile memory has been executed correctly.

Further, as described in claim 4, the above object is to store the characteristic value representing the state of the vehicle in the volatile memory, and to make the data in the volatile memory non-volatile under a predetermined condition. In a data recording device for a vehicle for writing data in a volatile memory to save data, under the predetermined conditions,
Data writing means for writing the data in the volatile memory to the non-volatile memory, voltage monitoring means for monitoring the voltage supplied to the data writing means, and the data during the data writing to the non-volatile memory. It is also achieved by a vehicle data recording device including a voltage state recording unit that writes determination data corresponding to whether or not the voltage supplied to the writing unit is equal to or lower than a predetermined voltage, to the nonvolatile memory.

In the present invention, the voltage monitoring means monitors the voltage supplied to the data writing means. The data writing unit appropriately records the data in the volatile memory in the non-volatile memory when a sufficient voltage is supplied. On the other hand, if the supplied voltage is insufficient, the data in the volatile memory cannot be properly recorded in the nonvolatile memory. The voltage state recording means writes, in the non-volatile memory, discrimination data indicating whether or not the voltage necessary for properly writing data is supplied to the writing means. In this case, the discrimination data indicates whether or not the data recorded in the non-volatile memory has an appropriate value.

Further, as described in claim 5, the above-mentioned object is, in the vehicle data recording apparatus according to claim 4, wherein the voltage state recording means is such that the voltage supplied to the data writing means is a predetermined voltage. It is also achieved by a vehicle data recording device including a normal voltage area recording unit that records progress data corresponding to a progress state of writing data to the nonvolatile memory in the nonvolatile memory when the value exceeds .

In the present invention, when a sufficient voltage is supplied to the data writing means, the normal voltage area recording means causes the progress data indicating the progress of data writing to be recorded together with the characteristic value in the nonvolatile memory. Recorded in. On the other hand, when the sufficient voltage is not supplied to the data writing means, the progress data is not recorded in the nonvolatile memory. In this case, the progress data represents up to what point the data was written correctly, that is, up to which point the recorded data can be guaranteed to be accurate.

Further, as described in claim 6, the above-mentioned object is, in the vehicle data recording apparatus according to claim 4, wherein the voltage state recording means is writing data into the nonvolatile memory, Vehicle data including abnormal time point recording means for recording, in the nonvolatile memory, progress data corresponding to the progress state of data writing at the time when the voltage supplied to the data writing means becomes equal to or lower than a predetermined voltage. It is also achieved by a recording device.

In the present invention, when a sufficient voltage is supplied to the data writing means to a state in which the voltage is insufficient, the abnormal time recording means indicates the data recording state at that time. Progress data,
Recorded in non-volatile memory. In this case, the progress data indicates at what point in time the data is likely to be inaccurate.

[0023]

FIG. 1 shows a system configuration diagram of an embodiment of the present invention. This embodiment is an example in which the vehicle data recording device is incorporated into a vehicle airbag system.
The system of this embodiment is controlled by the microcomputer 10. The microcomputer 10 has an A / D
The converter 10a is built in. The acceleration sensor 12 is connected to the A / D converter 10a. The acceleration sensor 12 detects the longitudinal acceleration acting on the vehicle and outputs a G signal corresponding to the magnitude of the acceleration. The G signal emitted from the acceleration sensor 12 is converted into a digital signal by the A / D converter 10a and then taken into the microcomputer 10. Microcomputer 10
Has a built-in RAM 10b, which is a volatile memory,
The G signal fetched as described above is stored in the RAM 10b at any time.

The microcomputer 10 also includes an E
The EPROM 14 is connected. EEPROM14
Is a non-volatile memory whose stored contents can be erased or rewritten by supplying a predetermined electric signal. In the system of this embodiment, the acceleration sensor 12
When the deceleration exceeding the predetermined level is detected by, the acceleration data stored in the RAM 10b becomes
It is written in the EEPROM 14. After that, the acceleration data written in the EEPROM 14 is saved without being erased even after the power of the airbag system is cut off.

A 5V power supply circuit 16 is connected to the power supply terminal of the microcomputer 10. The 5V power supply circuit 16 changes the voltage of 14V generated by the booster circuit 18 to 5V.
The voltage is stepped down and supplied to the microcomputer 10.
An on-vehicle battery 22 that generates a voltage of 12 V is connected to the booster circuit 18 via a diode 20. The airbag system of the present embodiment is a system for igniting an airbag by passing an electric current through a squib 24 described later. In the sense of reliably igniting the airbag,
The voltage supplied to the squib 23 is preferably high voltage. Therefore, in the system of the present embodiment, the booster circuit 18
Is used to generate a voltage of 14 V, which is higher than the voltage generated by the on-vehicle battery 22.

The diode 2 is provided on the output side of the booster circuit 18.
4, a backup circuit including a resistor 26, and a capacitor 28 is connected, and a safing sensor 30 and a resistor 32 are connected. The safing sensor 30 is a mechanical deceleration sensor that is turned on when a deceleration exceeding a predetermined value acts on the vehicle.
A resistor 32 connected in parallel with the safing sensor 30.
Is an element arranged to detect a disconnection around the squib 23 and has a sufficiently large resistance value.

The other end of the safing sensor 30 and the other end of the resistor 32 are connected to the squib 23. Furthermore,
The other end of squib 23 has a transistor 34 and a resistor 36.
Grounded. The transistor 34 is a switching element driven by the microcomputer 10, and is turned on when an airbag operating condition is satisfied, such as a deceleration exceeding a predetermined value acting on the vehicle. The resistor 36 connected in parallel with the transistor 34 is an element arranged to detect disconnection around the squib 23, like the resistor 32 described above, and has a sufficiently large resistance value.

When either the safing sensor 30 or the switching element 34 is off, the squib 23
The electric current flowing through is slightly suppressed. In this case, the squib 23 is not ignited and the airbag is not expanded. Further, under such a circumstance, electric charge flows into the capacitor 28 via the resistor 26 of the backup circuit, and the capacitor 28 is charged.

When the microcomputer 10 determines that the airbag operating condition is satisfied and the deceleration exceeding the predetermined value acts on the safing sensor 30, both the transistor 34 and the safing sensor 32 are turned on. It becomes a state. When both of them are turned on, the output voltage of the booster circuit 18 is applied to both ends of the squib 23, and a predetermined current flows through the squib 23. When such a current flows, the squib 23 is ignited and the airbag is expanded. The battery 22 may be damaged when the airbag is to be expanded. When the battery 22 is damaged, the electric charge stored in the capacitor 28 of the backup circuit is transferred to the diode 2
4 is discharged, and the discharge current ignites the squib.

A lamp drive circuit 40 is connected to the microcomputer 10 via a diode 38. A lamp 42 whose one end is connected to a power supply line is connected to the lamp connection circuit 40. The microcomputer 38 maintains the terminal connected to the diode 38 at a high output when the system is functioning normally. In this case, the terminal of the lamp drive circuit 40 connected to the lamp 42 is maintained at a high output. Therefore, under such a condition, no current flows through the lamp 42, and the lamp is maintained in the off state. On the other hand, the microcomputer 10
When detects an abnormality in the system, the terminal of the microcomputer 38 connected to the diode 38 is output low. In this case, the lamp 42 of the lamp drive circuit 40
The terminal connected to is changed to a low output and the lamp 42 is turned on. In the system of this embodiment, the system occupancy is displayed to the vehicle occupant in this way.

As described above, the microcomputer 10
R is detected when a deceleration exceeding a predetermined level is detected.
A process of writing the acceleration data in the AM 10b into the EEPROM 14 is executed. The data writing process is executed when the airbag operating condition is satisfied. In addition, the microcomputer 10 executes the above-described writing process so that the acceleration data for a predetermined period before and after the airbag operating condition is satisfied is stored in the EEPROM 14.

Writing data to the EEPROM 14 requires a longer time than writing data to the RAM 10b. Therefore, the G signal is sent in real time to the E signal.
It cannot be written to the EPROM 14. On the other hand, as in the system of this embodiment, the G signal is once sent to the RAM 1
0b and then EE the data in RAM 10b.
If the data is written to the PROM 14, the acceleration data is not limited to the time constraint and the EEPROM 14 can store the acceleration data.
Can be recorded within. If the acceleration data before and after the airbag operating condition is satisfied can be stored in the EEPOM 14, the data can be read out later to analyze the vehicle behavior before and after the airbag is activated. Therefore, the airbag system of the present embodiment is useful for accurately analyzing the cause of a vehicle accident or the like.

By the way, under the condition that the operating condition of the airbag is satisfied, the vehicle-mounted battery 22 may be damaged or the power supply system may be broken. If such damage or disconnection occurs, the supply voltage to the microcomputer 10 may drop, and the microcomputer 10 may not operate normally.

FIG. 2 shows the state of the voltage change of the 12V line when the vehicle-mounted battery 22 is damaged at time T ₀ . In the system of this embodiment, a power supply voltage of 6 V or higher is required for the booster circuit 18 to operate normally. Therefore, in the example shown in FIG. 2, the booster circuit 18 and the 5V power supply 16 cannot generate an appropriate voltage in a region after time T ₁ when the power supply voltage is less than 6V. Further, in the situation where the 5V power supply 16 cannot generate an appropriate voltage, the microcomputer 10 cannot operate normally. Therefore, the operation of the microcomputer 10 may stop in the area after the time T ₁ .

As described above, the data in the RAM 10b is stored in the E
It takes a relatively long time to write to the EPROM 14. Therefore, if the power supply voltage drops as shown in FIG. 2 after the airbag operating conditions are satisfied, the RAM
A situation may occur in which the operation of the microcomputer 10 is stopped while the data in 10b is being written in the EEPROM 14.

In the system of this embodiment, the EEPR
The writing of data to the OM 14 is executed when the microcomputer 10 detects a deceleration of a predetermined level. At this time, if the safing sensor 32 is turned on at the same time, the data is written and the airbag is activated, while if the safing sensor 32 is turned off, only the writing of data is performed. If only data is written, the data will be stored in the EEPROM 14 without being analyzed. In this case, when the data write condition is satisfied again later, a process of rewriting the acceleration data previously written in the EEPROM 14 to the latest acceleration data is performed.

FIG. 3 shows that when the above-mentioned data rewriting is executed, the latest acceleration data is EEPRO to the end.
The data waveform at the time of being written in M14 is shown. Also,
FIG. 4 shows that when the above-mentioned data rewriting is executed,
The data waveform when the rewriting of the latest acceleration data is stopped halfway due to the drop of the power supply voltage is shown.

As shown in FIG. 3, if the data in the EEPROM 14 are all the latest acceleration data, the data can be used to accurately analyze the vehicle behavior before and after the airbag is actuated. On the other hand, as shown in FIG. 4, the latest acceleration data (data of period C in FIG. 4) and acceleration data before that (data of period D in FIG. 4) are EEPR.
If they are mixed in OM14, based on the data,
It is difficult to accurately analyze the vehicle behavior before and after the airbag is activated. Further, if only the acceleration data is recorded in the EEPROM 14, when the data is read out later, whether the data was properly written to the end as shown in FIG. 3 or shown in FIG. It is impossible to judge whether the vehicle was stopped halfway.

The system of this embodiment has an EEPROM 14
When writing the data to, the data for determining whether or not the writing of the acceleration data has been completed properly,
By storing the data in the EEPROM 14 together with the acceleration data, the acceleration data in the EEPROM 14 is only the latest acceleration data when the data is analyzed, or the latest acceleration data and the previous acceleration data are mixed. It has the feature of being able to determine whether or not.

FIG. 5 and FIG. 6 show a flow chart of an example of a control routine executed by the microcomputer 10 to realize the above function. FIG. 5 is a timed interrupt routine that is activated every predetermined time, for example, every 0.35 msec, and FIG. 6 is a main routine that is always executed while the vehicle is operating.

When the routine shown in FIG. 5 is started, first in step 100, the write start flag is reset to "0". The write start flag is set to E as described later.
This flag is set to "1" when the condition for writing data in the EPROM 14 is satisfied.

In step 102, the acceleration detection value detected by the acceleration sensor 12 is the acceleration data gn.
It is recorded as (n = 1 to 4). 1 is assigned to n when the microcomputer 10 is initialized. Therefore, this processing is performed by the microcomputer 1
In the case of the first processing after 0 is started, the acceleration detected this time is recorded as the acceleration data g ₁ .

At step 104, the condition of n ≧ 4 is satisfied.
It is determined whether or not to stand. When n ≧ 4 is not satisfied
Is incremented by n in step 106
You. As a result, this routine is executed until n ≧ 4 holds.
Each time it is started, the acceleration is detected in step 102.
The values are sequentially g₁~ G_FourWill be recorded as. one
On the other hand, if it is determined that n ≧ 4 holds, step 1
At 08, g₁~ G _FourAcceleration data integrated value Gs
Is calculated, and 1 is substituted for n in the subsequent step 110.
You. Therefore, after this, every time this routine is started, acceleration is performed.
Degree detection value is g₁~ G _FourWill be recorded in this order.

At step 112, it is judged if the integrated value ∫Gdt of the acceleration detection value G over a predetermined period is greater than or equal to a predetermined value α. If ∫Gdt ≧ α is not established, it is determined that the vehicle is not improperly decelerated, and in step 114, the process of setting the write start flag to “0” is executed. On the other hand, when ∫Gdt ≧ α is established, it is soldered that the vehicle is being improperly decelerated, and in step 116, the process of setting the write start flag to “1” is executed.
When the processing of step 114 or 116 is completed, the acceleration data Gs calculated in step 108 is RA
The process for recording in M10b is executed. In the present embodiment, among the memory areas of the RAM 10b, 96 memory areas shown in FIG. 7 are allocated as areas for recording acceleration data. The writing of the acceleration data Gs to the memory area is performed in step 11 shown in FIG.
It is performed by the processing of 8 to 128.

That is, in step 112, ∫
If it is determined that the condition of Gdt ≧ α is not satisfied and the process of step 114 is executed, then step 11
At 8, it is determined whether or not the acceleration data Gs has been updated by this processing. As a result, when it is determined that Gs is not updated, the acceleration data Gs is set to RA.
It is judged that it is not necessary to record in M10b, so step 1
20 and 122 are jumped. On the other hand, if the Gs is judged to have been updated, in step 120, the acceleration data recorded in the G ₂ ~G ₆₄ regions of RAM10b is, is incremented in G ₁ ~G ₆₃ regions, respectively. Next, in step 122, the latest acceleration data Gs is recorded in the G ₆₄ area. Therefore, if the condition of step 112 is not satisfied, the latest 6
4 of the acceleration data Gs is to be recorded in the G ₁ ~G ₆₄ region of the RAM 10b.

When the condition of step 112 is satisfied and the process of step 116 is executed, next, at step 124, it is judged if the acceleration data Gs is updated by the current process. As a result, if it is determined that Gs has not been updated, it is determined that it is not necessary to record the acceleration data Gs in the RAM 10b, and steps 126 and 128 are skipped. On the other hand, if it is determined that Gs has been updated, in step 126, the latest acceleration data Gs is recorded in the G _{64 + m} area of the RAM 10b. Further, in the following step 128, a process of incrementing m is executed. “1” is substituted for m when the microcomputer 10 is initialized. Therefore, the above step 112
If the condition of is satisfied, then Gs calculated every predetermined time (in this embodiment, every 0.35 × 4 = 1.4 msec) is sequentially recorded in the area of G _{65 to} G _96. Become.

After the above processing is completed, next, at step 130, it is judged if the airbag operating condition is satisfied. As a result, when it is determined that the operating condition is satisfied, the routine proceeds to step 132, a drive signal for turning on the transistor 34 is generated, and then the routine of this time is ended. On the other hand, if it is determined that the operating condition is not satisfied, step 132 is skipped,
The processing of this time is ended as it is.

The acceleration data Gs recorded in the RAM 10b as described above is EEPRO when the microcomputer 10 executes the main routine shown in FIG.
Written to M14. That is, when the routine shown in FIG. 6 is started, first, at step 200, it is judged if the write start flag is set to "1" or not. If "1" is not set in the write start flag, it is determined that it is not necessary to write data in the EEPROM 14, and the routine of this time is ended as it is. On the other hand, when the write start flag is set to "1", the process of step 202 is executed to start writing the data to the EEPROM 14.

By the way, the EEPROM 14 has recording areas A _{0 to} A ₂₅₅ , as shown in FIG. RAM
The acceleration data Gs recorded in 10b is recorded in the areas A _{0 to} A ₉₅ of these recording areas. In this embodiment, one of the areas not used for recording the acceleration data Gs, for example, the A ₂₅₅ area is used as the in-writing flag area. Step 20
In 2, the EEPR is written in the writing flag area A ₂₅₅ .
Discrimination data "0A" is recorded to indicate that the writing of data to the OM 14 is started.

Next, in step 204, EEPOM1
“0” is assigned to the pointer P that specifies in which area of 4 the acceleration data Gs is to be recorded. When "0" is assigned to the pointer P in this way, the acceleration data Gs in the RAM 10b is recorded in the A ₀ area of the EEPROM 14.

In step 206, the acceleration data Gs recorded in any recording area in the RAM 10b is set to E
“1” is substituted into the address designation value x that designates whether to record in the EPROM 14. In this way, the address specification value x is "1"
When is substituted, the acceleration data Gs recorded in the recording area G ₁ in the RAM 10b is recorded in the EEPROM 14.

In step 208, in the recording area Ap of the EEPROM 14 corresponding to the pointer P, the acceleration data Gs in the recording area of the RAM 10b corresponding to the designated address value x.
Is written. Then, in step 210, the pointer P
Is incremented, the designated address value x is incremented in step 212.

At step 214, it is judged if the pointer P is larger than the predetermined value 95. If P> 95 is not satisfied, the processes of steps 208 to 214 are repeatedly executed. As a result, the acceleration data Gs recorded in each of the recording areas G _{1 to} G ₉₆ of the RAM 10b is written in each of the recording areas A _{0 to} A 95 of the EEPROM 14.

[0054] In step 214, when it is judged P> 95 is satisfied, then in step 216, the write flag area A _255, discrimination data indicating that the write data has been completed "A0" is written After this, this routine ends.

As described above, in the system of this embodiment, the EEPROM 14 is set in the writing flag area A ₂₅₅ .
The discrimination data “0A” is written at the time when the writing of the data to is started. Further, when the writing of the data to the EEPROM 14 is completed, the discrimination data “A0”
Is written. Therefore, when the data in the EEPROM 14 is read and analyzed, if "A0" is recorded in the writing flag area, it is determined that all the data stored in the EEPROM 14 is the latest acceleration data. can do. If "0A" is recorded in the writing flag area, it can be determined that the latest acceleration data Gs and the previously recorded acceleration data Gs are mixed in the EEPOM 14.

As described above, according to the system of the present embodiment, the EEPROM 14 stores not only the acceleration data but also the discrimination data indicating whether or not the stored acceleration data is accurate data for analyzing the vehicle behavior. Can be recorded. Therefore, according to the system of this embodiment, the EE
Accurate accident analysis can be realized as compared with a system in which only acceleration data is recorded in the PROM 14.

The RAM 10 is used in the above embodiment.
b is the volatile memory according to claim 1 and has an EEPROM
14 correspond to the non-volatile memory according to claim 1 respectively. Further, in the above embodiment, the microcomputer 10 executes the steps 200 and 20.
The data writing unit according to claim 1 is realized by executing the processes of 4 to 214, and the operation state recording unit according to claim 1 is realized by executing the processes of steps 202 and 216. .

Further, the microcomputer 10 executes the processing of the above step 202 so that the above-mentioned claim 2 is realized.
The start data recording means described above is also used in the above step 21.
By executing the process of 6, the end data recording means according to the second aspect is realized.

FIG. 9 shows a flowchart of an example of a main routine executed in the system of the second embodiment of the present invention. This embodiment has a system configuration similar to that of the first embodiment shown in FIG.
Is realized by executing the routine shown in FIG. 9 instead of the routine shown in FIG.

The routine shown in FIG. 6 is based on EEPOM1.
Microcomputer 10 during the writing of data to
If the operation of the
This routine is intended to be recorded in M14. When such processing is performed, it is possible to easily determine whether the stored data is accurate data or data including an inaccurate portion, as described above.

However, depending on the above routine, when incorrect data are mixed in the EEPROM 14, it is not possible to determine up to which area is the correct data and which area is the incorrect data. Can not. The present embodiment is characterized in that data (hereinafter referred to as progress data) for enabling such discrimination is recorded in the EEPROM 14.

The contents of the processing executed by the microcomputer 10 to realize the above functions will be described below with reference to FIG. In FIG. 9, the same steps as those shown in FIG. 6 are executed by the same reference numerals in parentheses, and the description thereof will be omitted or simplified.

When the routine shown in FIG. 9 is started, first, at step 300, it is judged if the write start flag is "1". As a result, when "1" is set in the flag, "0" is assigned to the pointer P and "1" is assigned to the address designation value x in step 302 and step 304, respectively. Then, step 30
6, the EEPROM 1 corresponding to the designated pointer P
RA corresponding to the specified address x in the recording area Ap of No. 4
The acceleration data Gs recorded in the recording area Gx in M10b is written.

Upon completion of the above processing, in this routine, in step 308, the writing flag area, that is, the A ₂₅₅ area of the EEPROM 14, is written.
The value of the pointer P is written. Then step 31
The pointer P and the address designation value x are incremented at 0 and 312, and the processes of steps 306 to 314 are repeatedly executed until it is determined at step 314 that P> 95 is satisfied. Then, in step 314, P>
When it is determined that 95 is satisfied, the routine of this time is ended.

When the microcomputer 10 executes the above main routine, the RAM is stored in the recording areas A _{0 to} A ₉₅ of the EEPOM 14 each time the above routine is started.
The acceleration data Gs recorded in the recording areas G _{1 to} G ₉₆ of 10b are sequentially written one by one, and EE
In the writing flag area A ₂₅₅ of the PROM 14, the value of the pointer P of the recording area in which the data was last written is written. In this case, the value recorded in the writing flag area A ₂₅₅ represents the last recording area that can be guaranteed as accurate data.

According to the system of this embodiment, EEPRO
When the data writing to M14 is properly executed to the end, the value “95” of the pointer P of the area to which the data is finally written is recorded in the writing flag area A ₂₅₅ . Further, if the microcomputer 10 is stopped during the writing of data to the EEPROM 14, the microcomputer 1 is set in the writing flag area A _255.
Before 0 is stopped, the value of the pointer P in the area where the data was last written is recorded. Therefore, when the data is analyzed later, by reading the data written in A ₂₅₅ , it is possible to easily distinguish the accurate data from the inaccurate data. Therefore, according to the system of the present embodiment, it is possible to realize accurate accident analysis in a wider situation than the system of the first embodiment described above.

In the present embodiment, the microcomputer 10 causes the steps 300 to 306 and 31 to be executed.
By executing the processing of 0 to 314, the data writing means of claim 1 is realized, and by executing the processing of step 308, the operation state recording means of claim 1 is realized. Furthermore, in this embodiment, the microcomputer 10 executes the above step 30.
By executing the process of No. 8, the progress data recording means according to claim 3 is realized.

FIG. 10 shows a system configuration diagram of the third embodiment of the present invention. In FIG. 10, the same parts as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The system according to the present embodiment includes the on-vehicle battery 22.
The output voltage Vbatt is connected to the A / D converter 10a of the microcomputer 10 via the diode 44, and the microcomputer 10 is characterized by monitoring Vbatt.

As described above, the microcomputer 10
Cannot operate normally when the voltage supplied to the booster circuit 18, that is, the battery voltage Vbatt becomes less than 6V. The battery voltage Vbatt drops to less than 6V when the vehicle-mounted battery 22 is damaged or the power supply line is disconnected. On the other hand, if these abnormalities do not occur in the power supply system, the battery voltage Vbatt is maintained near 12V. Therefore, if the battery voltage Vbatt is maintained near 12V after the airbag operating condition is satisfied, it can be estimated that the microcomputer 10 continues to operate normally, and Vbatt is greatly reduced from 12V. If so, it can be estimated that Vbatt <6V will eventually hold and the operation of the microcomputer 10 will be stopped.

Therefore, in this embodiment, when the battery voltage Vbatt exceeds 8V, it is determined that the microcomputer 10 is operating normally, while Vbatt
Is less than 8V, the microcomputer 10
Will be unable to operate normally. Then, the acceleration data G is stored in the EEPROM 14.
The determination data based on the battery voltage Vbatt is recorded together with s. If such determination data is recorded in the EEPROM 14, it is possible to easily determine whether the recorded data is accurate data when analyzing the data later.

FIG. 11 shows a flow chart of an example of a main routine executed in the system of this embodiment. The above functions are realized by the microcomputer 10 constituting the system shown in FIG. 10 executing the interrupt routine shown in FIG. 5 and the main routine shown in FIG. The contents of the main routine shown in FIG. 11 will be described below. In FIG. 11, steps that execute the same processing as the steps shown in FIG. 6 are given the same reference numerals in parentheses, and description thereof will be omitted or simplified.

When the routine shown in FIG. 11 is started, first, in step 400, the write start flag is set to "1".
Is set. If the write start flag is set to "1", step 402
In, the initial value “0” is substituted in the power supply flag area of the EEPROM 14. In the system of this embodiment,
In the recording area of the EEPROM 14, the battery voltage Vbatt
There is provided a power supply flag area for recording the determination data set corresponding to the value of. In this embodiment, the A ₂₅₄ area is used as the power supply flag area.

When the above processing is completed, step 40
In steps 4 and 406, "0" is assigned to the pointer P and "1" is assigned to the address designation value x, and then the process of step 408 is executed. In step 408, the A / D converter 10
It is determined whether or not the battery voltage Vbatt supplied to a exceeds 8V. As a result, if Vbatt> 8V is satisfied, steps 410 and 412 are jumped, and then the process of step 414 is executed.

In steps 414 to 420, the same processing as in steps 208 to 214 described above is executed. That is, in step 414, the process of recording the acceleration data Gs in the recording area Gx of the RAM 10b in the recording area Ap of the EEPROM 14 is executed. Also, step 4
At 16 and 418, the processing of incrementing the pointer P and the address designation value x is executed, respectively. Then, in step 420, it is determined whether or not the pointer P exceeds 95. As a result, when P> 95 is not satisfied, the processing of 408 and thereafter is repeatedly executed, and when P> 95 is satisfied, the routine of this time is ended.

If it is determined in step 408 that the battery voltage Vbatt is 8 V or less, the process proceeds to step 410, and the recording data in the power supply flag area is "0".
Is determined. As described above, "0" is recorded as the initial value in the power supply flag area (see step 402). Therefore, if the value has not been rewritten yet, the condition of step 410 is satisfied.

If it is determined in step 410 that the recording data in the power supply flag area is "0",
In step 412, the value of the pointer P designated in the current processing, that is, the value of the pointer P in the recording area in which the acceleration data is recorded in the current processing is written in the power flag area. In this way, "0" is set in the power supply flag area.
If P is not written, it is determined that the condition of step 410 is not satisfied in the subsequent processing.

Therefore, in the power supply flag area, the EEPR is
Vbatt> 8V even while writing data to OM14
If is not satisfied, "0" is saved and E
Vbatt> 8V while writing data to EPROM14
Is not established, the value of the pointer P of the recording area in which the data is being written is saved when Vbatt first becomes 8 V or less.

When such progress data is recorded in the power supply flag area, when the data is analyzed later, accurate acceleration data is recorded in the recording area before the pointer P recorded in the power supply flag area. Further, it can be recognized that acceleration data that may not be accurate is recorded in the recording area after the pointer P recorded in the power supply flag area. Therefore, according to the system of this embodiment, only the acceleration data is stored in the EEPROM 1.
A more accurate data analysis can be realized as compared to the system stored in 4.

Furthermore, according to the system of the present embodiment, until the possibility that the microcomputer 10 is stopped,
That is, until Vbatt becomes 8V or less, EEPRO
Only the acceleration data is written in M14. For this reason,
Each time the acceleration data is written to the EEPROM 14, it is necessary to store the data for determining the authenticity of the acceleration data, as compared with the system of the second embodiment, which writes the progress data indicating the progress state. Time and energy can be saved. Therefore, according to the system of the present embodiment, more accurate acceleration data can be obtained as compared with the system of the second embodiment in the case where the power supply is cut off early after the airbag is activated. You can save a lot.

By the way, in the present embodiment, the first
Recording processing executed by the system of the embodiment, that is, EE
Although the process of recording the start data and the end data indicating the start and the end of the writing of the data to the PROM 14 is not executed, it is also possible to execute both in combination. When the processing of the first embodiment and the processing of the third embodiment are executed in combination, the EEPROM 1
Of the acceleration data recorded in 4, accurate data and
It is possible to distinguish from data that may not be accurate, and it is possible to determine whether or not the data writing has been executed to the end. Therefore, if these processes are executed in combination, it is possible to realize more highly accurate data analysis as compared with the case where these processes are executed independently.

Incidentally, in the above embodiment, the microcomputer 10 executes the steps 400, 404, 40.
6, and 414 to 420, the data writing unit according to claim 4 performs the process of step 408, and the voltage monitoring unit according to claim 4 performs the processes of steps 402 and 408. ~ 4
The voltage state recording means according to claim 4 is realized by executing the processing of 12.

Further, in the above embodiment, the microcomputer 10 executes the processing of the steps 408 to 412 to implement the abnormal point recording means according to the sixth aspect. FIG. 12 shows a flow chart of the main routine executed in the system of the fourth embodiment of the present invention. This embodiment is realized by the microcomputer 10 executing the routine shown in FIG. 12 instead of the routine shown in FIG. 11 in the same system configuration as the third embodiment shown in FIG.

In the system of the third embodiment described above, the EEPROM 1 is set when the battery voltage Vbatt becomes 8 V or less.
It is a system that enables the distinction between the accurate data and the data that may not be accurate by recording the data in the memory 4. On the other hand, in the system of this embodiment, EEPRO is set in the region where the condition of battery voltage Vbatt> 8V is satisfied.
By recording the data in M14, it is a system that enables distinction between accurate data and data that may not be accurate.

The contents of the processing executed by the microcomputer 10 to realize the above functions will be described below with reference to FIG. In FIG. 12, steps that execute the same processing as the steps shown in FIG. 6 above are attached with the same reference numerals in parentheses, and description thereof will be omitted or simplified.

When the routine shown in FIG. 12 is started, first in step 500, the write start flag is set to "1".
Is set. If "1" is set in the write start flag, step 50
In steps 2 and 504, "0" is assigned to the pointer P and "1" is assigned to the address designation value x, and then the process of step 506 is executed. In step 506, the A / D converter 10
It is determined whether or not the battery voltage Vbatt supplied to a exceeds 8V. As a result, when Vbatt> 8V is satisfied, it is determined in step 508 whether or not the abnormality flag is set to "1". On the other hand, when Vbatt> 8V is not established, step 51
At 0, the abnormality flag is set to "1".

According to the above processing, if the condition of Vbatt> 8V is satisfied even once during the writing of data to the EEPROM 14, the abnormality flag is set to "1".
Therefore, the condition of step 508 is that the EEPROM 1
After the writing of data to 4 is started, it is continuously Vba
Only when tt> 8V is established, that is, EEP
Only when the writing of data to the ROM 14 is properly performed, the data is not established.

If it is determined in step 508 that the abnormality flag is not set to "1", then in step 512, the pointer P of the recording area in which the data is written by the current processing is written in the power flag area of the EEPROM 14. The value of is recorded. On the other hand, if it is determined in step 508 that the abnormality flag is set to "1", step 512 is skipped. In this case, the value of the pointer P recorded in the power supply flag area always corresponds to the last time point when the condition of Vbatt> 8V is continuously maintained. That is, when Vbatt never becomes 8 V or less during writing of data to the EEPROM 14, the value of the pointer P of the recording area where the data is finally written is finally written in the power supply flag area. 95 "is stored, and when the condition of Vbatt> 8V is not satisfied during the writing of data, the value of the pointer P of the recording area in which the data was written immediately before is saved in the power supply flag area. It will be.

When such data is recorded in the power supply flag area, when the data is analyzed later, accurate acceleration data is recorded in the recording area before the pointer P recorded in the power supply flag area. Also, it can be recognized that acceleration data that may not be accurate is recorded in the recording area after the pointer P recorded in the power supply flag area. Therefore, according to the system of the present embodiment, more accurate data analysis can be realized as compared with the system in which only acceleration data is stored in the EEPROM 14.

Upon completion of the above processing, the following steps 208 to 520 are followed in steps 514 to 520.
The same processing as that of 14 is executed, and when P> 95 is satisfied in step 520, the routine of this time is ended. By the way, in the present embodiment, unlike the system of the first embodiment, the process of recording the start data and the end data indicating the start and end of writing of data to the EEPROM 14 is not executed. Similar to the case of the third embodiment, when the processing of the present embodiment and the processing of the first embodiment are executed in combination, a higher precision data analysis is realized as compared with the case where both are executed independently. It becomes possible to do.

Incidentally, in the above embodiment, the microcomputer 10 executes the steps 500, 502, 50.
4, and 514 to 520 are executed, the data writing means according to claim 4 is executed, and the voltage monitoring means according to claim 4 is executed by executing the process of step 506. The voltage state recording means according to the fourth aspect is realized by executing the processing described in (4) above.

Further, in the above embodiment, the normal voltage region recording means according to claim 5 is realized by the microcomputer 10 executing the processing of the steps 508 to 512. By the way, in the system of the fourth embodiment, the battery voltage Vbatt> 8V
When is satisfied, the value of the pointer P is written in the power supply flag area every time the acceleration data is written in the recording area of the EEPROM 14. According to such a method, when data is read out and analyzed later, the area in which accurate data is recorded and the area in which data that may not be accurate are recorded are strictly separated. You can

However, since it takes a relatively long time to write the data to the EEPROM 14, if the pointer P is recorded every time one acceleration data is recorded, the data writing is started. After that, there is a high possibility that the battery voltage Vbatt will drop before the writing of all data is completed. In this sense, it is appropriate to keep the recording of the pointer P to a necessary minimum.

FIG. 13 shows a flowchart of the main routine executed in the system of the fifth embodiment of the present invention. The system of this embodiment is based on the above viewpoint.
This is a system provided for the purpose of reducing the number of times the pointer P is written. In the system of this embodiment, the microcomputer 10 executes the main routine shown in FIG. 13 instead of the routine shown in FIG. 11 using the same system configuration as that of the third embodiment shown in FIG. It is realized by

The contents of the processing executed by the microcomputer 10 to realize the above functions will be described below with reference to FIG. Incidentally, in FIG.
Steps that perform the same processing as the steps shown therein will be denoted by the same reference numerals in parentheses, and description thereof will be omitted or simplified.

In the routine shown in FIG. 13, in steps 600 to 610, the above-mentioned step 500 is executed.
The same processing as 510 is executed. If it is determined in step 608 that the abnormality flag is set to "1", in step 612 N is a predetermined value β.
It is determined whether or not this is the case. N is set to 1 when the microcomputer 10 is initialized. The predetermined value β is a constant related to the writing frequency of the pointer P, and is set to 4 in this routine, for example. Therefore, if the current process is the first process after the microcomputer 10 is started, the above step 6 is performed.
It is determined that the condition 12 is not satisfied.

If it is determined in step 612 that N ≧ β is not satisfied, then in step 614, N is incremented. In this case, step 6
18, that is, the step of recording the value of the pointer P in the power supply flag area (corresponding to the above step 512) is jumped. On the other hand, if it is determined in step 612 that N ≧ β is satisfied, N is “1” in step 616.
After being reset to, the processing of step 618 is executed. As a result, the writing of the pointer P to the power supply flag area is performed once every time β-times acceleration data is written in the EEPROM 14.

Therefore, according to the system of this embodiment, the acceleration data in the RAM 10b can be immediately written in the EEPROM 14 after the write start flag is set to "1". Therefore, according to the system of the present embodiment, in the case where the battery power supply Vbatt drops relatively early after the write start flag is set to "1", compared to the system of the fourth embodiment described above, More accurate data analysis can be realized.

When the above process is completed, the above-mentioned steps 514-5 are executed in steps 620-626.
The same process as 20 is executed. And step 52
In P6, if P> 95 is satisfied, the routine of this time is ended. In the present embodiment, unlike the system of the first embodiment, the process of recording the start data and the end data indicating the start and end of the writing of data to the EEPROM 14 is not executed. As in the case of the fourth embodiment, the processing of this embodiment,
When executed in combination with the processing of the first embodiment, it is possible to realize more highly accurate data analysis compared to the case where both are executed independently.

Incidentally, in the above embodiment, the microcomputer 10 executes the steps 600, 602, 60.
4, and 620 to 626, the data writing unit according to claim 4 performs the process of step 606, and the voltage monitoring unit according to claim 4 performs the steps of 608 to 618. The voltage state recording means according to the fourth aspect is realized by executing the processing described in (4) above.

Furthermore, in the above embodiment, the microcomputer 10 executes the processes of steps 608 to 618 to implement the normal voltage region recording means according to the fifth aspect. By the way, in the systems of the first to fifth embodiments described above, the data recorded in the EEPROM 14 is limited to acceleration data, but the present invention is not limited to this. That is, characteristic values representing the state of the vehicle, such as the vehicle yaw rate γ, the steering angle δ, and the vehicle speed V, may be recorded together with the acceleration data or instead of the acceleration data.

[0101]

As described above, according to the first aspect of the invention, the non-volatile memory records the characteristic value indicating the state of the vehicle and the discrimination data indicating whether or not the characteristic value is normally recorded. can do. When the discrimination data is recorded, it is possible to easily determine whether or not the data to be analyzed is accurate, so that the characteristic value analysis with high accuracy can be performed. As described above, according to the vehicle data recording device of the present invention, it is possible to highly accurately store sufficient data in the non-volatile memory for performing the characteristic value analysis.

According to the second aspect of the present invention, the start data indicating the start of writing data to the non-volatile memory and the end data indicating the end of writing can be recorded in the non-volatile memory. When the data recorded in the non-volatile memory is analyzed, if the end data is written after the start data, it can be determined that the latest characteristic value is appropriately recorded in the non-volatile memory. If the end data is not written after the start data,
It can be determined that the latest characteristic value and the previous characteristic value are mixed in the non-volatile memory. As described above, according to the vehicle data recording device of the present invention, sufficient data for accurately and easily determining the identity of the data recorded in the non-volatile memory is stored in the non-volatile memory. be able to.

According to the third aspect of the present invention, it is possible to record, in the non-volatile memory, progress data indicating to what point the data writing to the non-volatile memory has been correctly executed. Therefore, when the data in the non-volatile memory is read and analyzed, it is possible to easily determine up to what time the data is an accurate value as the current characteristic value based on the progress data. As described above, according to the vehicle data recording device of the present invention, it is possible to store, in the non-volatile memory, the upper part necessary for distinguishing the data to be used for analysis and the data that should not be used for analysis. it can.

According to the fourth aspect of the present invention, it is possible to record the discrimination data corresponding to whether or not the voltage required for the data writing means to operate properly in the non-volatile memory. Therefore, when analyzing the data in the non-volatile memory, it is possible to easily determine whether or not the data in the non-volatile memory is accurate based on the determination data.

According to the fifth aspect of the invention, it is possible to record the progress data indicating to what point the data writing means has properly written the data in the non-volatile memory. Therefore, according to the present invention, when the data in the non-volatile memory is read and the characteristic value is analyzed, the data that can be guaranteed to be accurate and the data that can be guaranteed to be accurate based on the progress data. It can be easily distinguished from data that cannot be obtained.

According to the invention as set forth in claim 6, it is possible to record in the nonvolatile memory the time when the state in which it cannot be guaranteed that the data writing means operates properly is recorded. Therefore, according to the present invention, when the data in the non-volatile memory is read and the characteristic value is analyzed, the data that can be guaranteed to be accurate and the data that can be guaranteed to be accurate based on the progress data. It can be easily distinguished from data that cannot be obtained.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a first embodiment of the present invention.

FIG. 2 is a diagram showing a state in which a battery voltage drops.

[Fig. 3] EE when data writing is completed
It is an example of the data waveform recorded in POM.

FIG. 4 EE when data writing is stopped halfway
It is an example of the data waveform recorded in POM.

FIG. 5 is a flowchart of an example of an interrupt routine executed by the system according to the first embodiment of this invention.

FIG. 6 is a flowchart of an example of a main routine executed by the system according to the first embodiment of this invention.

FIG. 7 is a diagram showing a recording area in a RAM included in a microcomputer.

FIG. 8 is a diagram showing a recording area in an EEPROM.

FIG. 9 is a flowchart of an example of a main routine executed by the system of the second embodiment of the present invention.

FIG. 10 is a system configuration diagram of a third embodiment of the present invention.

FIG. 11 is a flowchart of an example of a main routine executed by the system of the third embodiment of the present invention.

FIG. 12 is a flowchart of an example of a main routine executed by the system of the fourth embodiment of the present invention.

FIG. 13 is a flowchart of an example of a main routine executed by the system of the fifth embodiment of the present invention.

[Explanation of Codes] 10 Microcomputer 10b RAM (volatile memory) 12 Acceleration sensor 14 EEPROM (nonvolatile memory) 16 5V power supply 18 Booster circuit 22 In-vehicle battery

Claims (6)

[Claims] 1. Vehicle data for storing a characteristic value representing a vehicle state in a volatile memory, and for saving the data by writing the data in the volatile memory to a non-volatile memory under a predetermined condition. In the recording device, under the predetermined condition, the data in the volatile memory,
Data writing means for writing to the nonvolatile memory, and an operation state record for writing, to the nonvolatile memory, determination data corresponding to whether or not the operation of the data writing means has stopped during data writing to the nonvolatile memory. A data recording device for a vehicle, comprising: 2. The vehicle data recording apparatus according to claim 1, wherein the operation state recording means records start data in the non-volatile memory when writing of data in the non-volatile memory is started. A vehicle data recording device comprising: start data recording means; and end data recording means for recording end data in the non-volatile memory when writing of data to the non-volatile memory is completed. . 3. The vehicle data recording device according to claim 1, wherein the operation state recording unit records, in the non-volatile memory, progress data corresponding to a progress state of writing data in the non-volatile memory. A vehicle data recording device comprising a progress data recording means. 4. Vehicle data for storing a characteristic value representing a vehicle state in a volatile memory, and for saving the data by writing the data in the volatile memory to a non-volatile memory under a predetermined condition. In the recording device, under the predetermined condition, the data in the volatile memory,
Data writing means for writing to the non-volatile memory, voltage monitoring means for monitoring a voltage supplied to the data writing means, and a voltage to be supplied to the data writing means is predetermined during data writing to the non-volatile memory. A vehicle data recording device comprising: a voltage state recording unit that writes determination data corresponding to whether or not the voltage is equal to or lower than a voltage into the nonvolatile memory. 5. The vehicle data recording device according to claim 4, wherein the voltage state recording means is configured to write data to the nonvolatile memory when the voltage supplied to the data writing means exceeds a predetermined voltage. A data recording device for a vehicle, comprising: a normal voltage area recording unit for recording progress data corresponding to the progress state of writing in the non-volatile memory. 6. The vehicle data recording device according to claim 4, wherein the voltage state recording means is such that a voltage supplied to the data writing means is equal to or lower than a predetermined voltage during writing of data in the nonvolatile memory. A vehicle data recording device comprising: an abnormal time recording means for recording, in the nonvolatile memory, progress data corresponding to a progress state of data writing at that time.