JP3500767B2 - Acceleration detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration detecting device for detecting an acceleration applied to a vehicle, and in particular, when the vehicle is subjected to an impact of a predetermined value or more, the detected acceleration data is displayed along a time axis. The present invention relates to an acceleration detecting device capable of storing a plurality of items.

[0002]

2. Description of the Related Art In recent years, when a vehicle is impacted with a predetermined value or more due to a vehicle collision or the like, a squib ignites a gas generating agent, and the generated gas causes an airbag or a seat belt with a preloader. The vehicle protection device for driving the above-mentioned protective equipment has come to be mounted. Such a vehicle protection device has an electronic control unit (Electronic Control Unit; hereinafter referred to as ECU) for controlling and igniting the squib when an impact of a predetermined value or more is applied to the vehicle. In general, the protective device ECU includes an acceleration sensor for detecting an acceleration applied to the vehicle, a central processing unit (CPU) for controlling a squib based on the detected acceleration, and the like.

In a conventional vehicle protection device, as a protection device ECU, a front collision is provided with a longitudinal acceleration sensor for detecting longitudinal acceleration in order to cope with a collision (front collision) at the front of the vehicle. In addition to the vehicle side ECU, there is a case where the vehicle side collision ECU is provided with a lateral acceleration sensor that detects a lateral acceleration in order to cope with a collision (side collision) on the side of the vehicle. In this case, the front collision ECU is usually installed near the floor tunnel of the vehicle, but the side collision ECU is
Is required for high-speed sensing by the lateral acceleration sensor, so it is installed inside the vehicle door panel.
Both were operating independently of each other.

On the other hand, in the conventional vehicle protection device,
In order to analyze the accident after it has occurred, EC
There is a case where a waveform memory for storing a waveform showing a temporal change in acceleration detected by the acceleration sensor is built in U. That is, when the vehicle is impacted by a predetermined value or more due to a vehicle collision or the like, the waveform indicating the time change of the acceleration detected by the acceleration sensor is stored in the waveform memory of the ECU, and the ECU is recovered from the vehicle after the accident occurs. Then, the waveform stored in the waveform memory is read to analyze the impact applied during the vehicle collision.

Therefore, the front impact ECU and the side impact E described above are used.
In the vehicle protection device having a CU, when the above-mentioned waveform memory is built in the ECU, the waveform memory is separately built in each of the front collision ECU and the side collision ECU. Then, the ECU for frontal collision stores the waveform showing the temporal change of the acceleration in the front-rear direction in the waveform memory, and
In U, the waveform showing the temporal change of the acceleration in the left-right direction is stored in the waveform memory.

[0006]

Since the front collision ECU and the side collision ECU operate independently of each other, they are independent from each other when the waveform showing the time change of the detected acceleration is stored in the waveform memory. I had it remembered. Therefore, by reading the waveforms stored in each waveform memory, it is possible to understand the temporal changes in the longitudinal acceleration and the lateral acceleration, but the temporal correspondences between them. Since the relationship is unknown, there was a problem that it caused problems when performing comprehensive analysis.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to easily grasp the temporal correspondence between the stored acceleration data in two directions. It is to provide a detection device.

[0008]

In order to achieve the above-mentioned object, the invention according to claim 1 is an acceleration detecting device mounted on a vehicle, wherein A first acceleration sensor that detects a first acceleration applied in a direction, and a second acceleration sensor that detects a second acceleration applied to the vehicle in a second direction different from the first direction, Storage means having a plurality of storage areas and data of the first acceleration detected when a shock of a predetermined value or more is applied to the vehicle in the first direction. Is written in the storage means along the time axis, and when an impact of a predetermined value or more is applied to the vehicle in the second direction, the second detection is performed when the impact is applied. Acceleration data of multiple before along the time axis And a writing means for writing in the memory means, said writing means, said detected first
When both the data of the second acceleration and the data of the second acceleration are written in the storage means, it is characterized in that the information representing the temporal correspondence between the two is also written.

As described above, in the invention described in claim 1,
The data of the first acceleration detected by the first acceleration sensor and the data of the second acceleration detected by the second acceleration sensor are written in the same storage means, and information indicating the temporal correspondence between the two is written. Is also written.

According to a second aspect of the present invention, in the acceleration detecting device according to the first aspect, the writing means stores only data of one of the detected first and second accelerations in the storage means. In the case of writing data into, the data amount of the data to be written is set to be larger than the data amount of one data in the case of writing both the first acceleration data and the second acceleration data.

As described above, according to the second aspect of the invention,
When only the data of one of the detected first and second accelerations is written in the storage means, for example, by shortening the sampling interval of the data of the detected acceleration, the data amount of the written data is The data amount is larger than the data amount of one data when writing both the first and second acceleration data.

According to a third aspect of the present invention, there is provided an acceleration detecting device mounted on a vehicle, the first acceleration sensor detecting a first acceleration applied to the vehicle in a first direction; A second acceleration sensor for detecting a second acceleration applied to the vehicle in a second direction different from the first direction, a storage unit having a plurality of storage areas, and a first unit for the vehicle. When a shock of a predetermined value or more is applied to either one of the first and second directions, the data of both the first and second accelerations detected when the shock is applied are taken along the time axis. And a writing means for writing a plurality of data to the storage means.

As described above, according to the invention of claim 3,
When an impact of a predetermined value or more is applied to either one of the first and second directions, both the data of the first and second accelerations detected when the impact is applied are stored in the same storage means. I am writing.

According to a fourth aspect of the present invention, in the acceleration detecting device according to the first, second or third aspect, the first direction is the front-rear direction of the vehicle and the second direction is the vehicle direction. In the left-right direction, the first acceleration sensor and the storage means are arranged near a floor tunnel of the vehicle, and the second acceleration sensor is arranged inside a door panel of the vehicle.

As described above, according to the invention described in claim 4,
An acceleration sensor for detecting an acceleration applied in the front-rear direction of the vehicle and a storage unit are arranged near a floor tunnel of the vehicle, and an acceleration sensor for detecting an acceleration applied in the left-right direction of the vehicle is arranged in a door panel of the vehicle.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a protective device ECU including an acceleration detecting device as an embodiment of the present invention. In the present embodiment, the vehicle protection device is provided with two protection device ECUs, a front collision ECU 10 and a side collision ECU 20, as shown in FIG. And ECU for frontal collision
10 has a waveform memory 13 as described later,
The side collision ECU 20 does not include a waveform memory, and instead, the front collision ECU 10 and the side collision ECU 20 are connected by a data line 30.

That is, the ECU 10 for the front collision includes the CPU 1
1, a longitudinal acceleration sensor 12, a waveform memory 13, a front collision safing sensor 14, and a FET 15. Of these, the CPU 11 is connected with the longitudinal acceleration sensor 12, the waveform memory 13 and the FET 15, and also with an external data line 30. The front impact safing sensor 14 has one end connected to an external power source and the other end connected to an external front impact squib 40, and an output end 1 for outputting a trigger.
4a is connected to the CPU 11. The FET 15 has a drain side connected to the front squib 40 and a source side connected to ground.

The side collision ECU 20 includes a CPU 21,
Left-right acceleration sensor 22, side impact safing sensor 2
4 and FET 25 are provided. Of these, the CPU 21 is connected with the lateral acceleration sensor 22 and the FET 25,
The external data line 30 is connected. The side impact safing sensor 24 has one end connected to an external power source, the other end connected to an external side impact squib 50, and an output end 24a for outputting a trigger connected to the CPU 21. F
The ET 25 has a drain side connected to the side impact squib 50 and a source side connected to ground.

The longitudinal acceleration sensor 12 is a so-called acceleration sensor using a semiconductor element, which constantly detects an acceleration applied to the vehicle in the longitudinal direction (hereinafter referred to as longitudinal acceleration) by converting it into an electric signal, and detects the acceleration. The detection result is output to the CPU 11. The lateral acceleration sensor 22 is also a similar acceleration sensor, and constantly detects an acceleration applied in the lateral direction (hereinafter, referred to as lateral acceleration) and outputs the detection result to the CPU 21.
Is output to. Further, under normal conditions, both the safing sensors 14 and 24 and the FETs 15 and 25 are off (OF
F) It is in a state.

Therefore, for example, when a large deceleration is applied in the front-rear direction due to a front collision and the deceleration exceeds the first set value, the front collision ECU 10 first detects the front collision safing sensor. 14 is turned on. When the front collision safing sensor 14 is turned on, the CPU 1
A trigger is output for 1. As will be described later, this trigger gives an opportunity to start writing the acceleration data.

After that, deceleration is further added, and it is determined that the value based on the deceleration (for example, moving average of deceleration for 10 msec) exceeds the second set value (> first set value). Is known from the detection result of the longitudinal acceleration sensor 12, the CPU 11 determines that there is a collision and turns on the FET 15. Thus, when both the front-collision safing sensor 14 and the FET 15 are turned on, a current of a predetermined value or more flows from the power source to the front-collision squib 40. As a result, the squib 40 for front impact is a gas generating agent (not shown).
Is ignited to generate gas, and the gas is used to deploy a front-collision airbag (not shown) or drive a preloader (not shown) to restrain the occupant of a seat belt (not shown). To increase

On the other hand, when a large amount of deceleration is applied in the left-right direction due to a side collision or the like, the side collision ECU 20 performs the same operation as that of the front collision ECU 10.
As a result, a current of a predetermined value or more flows through the side impact squib 50, and the side impact squib 50 ignites a gas generating agent (not shown), so that a side impact airbag (not shown).
And the effect of restraining the occupant of the seat belt (not shown).

Since the above-mentioned operations are independently performed in the front collision ECU 10 and the side collision ECU 20, respectively, when a large deceleration is applied only in the front-rear direction due to only the front collision, or only in the side collision. Therefore, when a large deceleration is applied only in the left-right direction, generally only one of the front collision ECU 10 and the side collision ECU 20 operates. However,
When a side collision occurs subsequent to the front collision or a front collision occurs subsequent to the side collision and a large deceleration is applied to both the front-rear direction and the left-right direction, the front collision ECU 10 and the side collision EC
Both U20s operate in parallel.

Next, the acceleration data writing process will be described. As described above, the writing of the acceleration data is started when the safing sensor 14 or 24 is turned on. Then, the writing mode at that time differs as follows depending on the ON / OFF states of the two safing sensors.

FIG. 2 is an explanatory view for explaining the difference in the writing form of the acceleration data according to the ON / OFF state of the safing sensor in FIG. As shown in FIG. 2, there are four writing modes.

Modes I and II are cases in which both the front and side collision safing sensors 14 and 24 are both turned on. In both cases, both longitudinal acceleration data and lateral acceleration data are written. . Among them, in the form I, the safing sensor 14 for frontal impact is the safing sensor 2 for side impact.
4 is ON before 4, and conversely, Form II is when the side impact safing sensor 24 is turned on before the front impact safing sensor 14.

Form III is a front impact safing.
This is a case where only the sensor 14 is turned on, and in this case, only the longitudinal acceleration data is written. In form IV, conversely, only the side impact safing sensor 24 is turned on. In this case, only the lateral acceleration data is written.

A code is assigned to each form. As shown in FIG. 2, for example, the code of form I is "0111", the code of form II is "0110", the code of form III is "0010", and the code of form IV is "0".
001 ".

FIG. 3 is a flowchart showing an example of acceleration data writing processing in the protective device ECU shown in FIG. The CPU 11 detects whether a trigger is input from the front-collision safing sensor 14 and determines whether the front-collision safing sensor 14 is turned on as shown in FIG. 3 (step S10). . Also, CP
U11 accesses the CPU 21 via the data line 30, detects whether a trigger is input from the side impact safing sensor 24 to the CPU 21, and determines whether the side impact safing sensor 24 is turned on. The determination is made (step S20). Then, for example, a frontal collision occurs and the CP
When U11 determines that the front-collision safing sensor 14 is turned on, the first writing process is performed (step S100), and a side collision occurs, and the CPU 21 causes the side-collision safing sensor 24 to operate. When it is determined that it is turned on, the second writing process is performed (step S200).

FIG. 4 is a waveform diagram showing a temporal change in acceleration detected by the longitudinal acceleration sensor 12 and the lateral acceleration sensor 22 shown in FIG. In FIG. 4, (a) shows a temporal change in the longitudinal acceleration detected by the longitudinal acceleration sensor 12, and (b) shows a temporal change in the lateral acceleration detected by the lateral acceleration sensor 22. (A),
In both (b), the horizontal axis represents time and the vertical axis represents acceleration. Further, in (a), the numbers with white circles show the sampling data of the detected longitudinal acceleration, and the numbers with black circles show the sampling data of the detected lateral acceleration, respectively.

FIG. 5 is an explanatory view schematically showing the division of storage areas in the waveform memory 13 of FIG. As shown in FIG. 5, the storage area of the waveform memory 13 includes a code storage area 130 for storing code data, a time difference storage area 132 for storing time difference data, and acceleration data (that is, shown in FIG. 4). It is divided into first and second acceleration data storage areas 134 and 136 for storing (acceleration sampling data).

FIG. 6 is a flow chart showing an example of the first write processing in FIG. 3, FIG. 7 is a flow chart showing an example of the second write processing in FIG. 3, and FIG. 8 is a flow chart of FIG. 5 by the write processing of FIGS. 6 is an explanatory diagram showing a transition of data written in the waveform memory 13. FIG.

The first write process (step S100) of FIG. 3 will be described with reference to FIGS. 6 and 8. As shown in FIG. 6, when the first writing process is started, C
PU11 sets the time t of the internal timer (not shown) of CPU11 to zero (step S102). And C
The PU 11 writes the longitudinal acceleration data detected by the longitudinal acceleration sensor 12 in the waveform memory 13 until the side collision safing sensor 24 is turned on (step S104) (step S106). Since the waiting time in step S110 is t0, the writing of the longitudinal acceleration data is performed almost every time t0. Therefore, as shown in FIG. 8A, the longitudinal acceleration data sampled in the first and second acceleration data storage areas 134 and 136 of the waveform memory 13 at intervals of approximately time t0 shown in FIG. Are written alternately. That is, the data indicated by plain white numbers are written in the first acceleration data storage area 134, and the data indicated by white circle numbers with '(apostrophe) are written in the second acceleration data storage area 136. Be done. In addition, the CPU 11 sets the elapsed time t of the internal timer to a preset time T every time the longitudinal acceleration data is written (step S106).
(See FIG. 4) is determined (step S
108).

Thus, as shown in FIG. 8D, only the longitudinal acceleration data is written in the first and second acceleration data storage areas 134 and 136, and the elapsed time t of the internal timer becomes equal to the set time T. If the side collision safing sensor 24 is not turned on before the time exceeds, the CPU 11 writes the form code in the code storage area 130 of the waveform memory 13 when the elapsed time t exceeds the set time T (step S112). The first writing process ends. That is,
In this case, only the front impact safing sensor 14 is ON.
Since this is the case, it corresponds to the form III shown in FIG. 2, and the code “0” is stored in the code storage area 130 as shown in E of FIG.
010 ″ will be written. Note that the time difference storage area 132 remains unused.

On the other hand, before the elapsed time t of the internal timer exceeds the set time T, the side impact safing sensor 24 is turned on.
Then, the process proceeds to step S114 according to the determination in step S104 in FIG. In step S114, the CPU 11
Refers to the elapsed time t of the internal timer, and after the side impact safing sensor 14 is turned on, the side impact safing
The time difference t1 (see FIG. 4) until the sensor 24 is turned on is calculated, and is written in the time difference storage area 132 of the waveform memory 13 as shown in B of FIG. Then, the CPU 11
The longitudinal acceleration data detected by the longitudinal acceleration sensor 12 is written in the waveform memory 13 (step S116).
In addition, the lateral acceleration data detected by the lateral acceleration sensor 22 is also written in the waveform memory 13 (step S1).
18). The lateral acceleration data is stored in the CPU 11
By accessing 21, the data is transferred from the CPU 21 via the data line 30.

The writing of the longitudinal acceleration data and the lateral acceleration data at this time requires that the waiting time in step S122 is twice that in step S210, that is, (2 × t).
0), and each is performed almost every time (2 × t0). Therefore, as shown in FIG.
Xt0) longitudinal acceleration data sampled at intervals (that is, data indicated by unmarked circles) and lateral acceleration data sampled at approximately time intervals (2xt0) (ie, 't'). The data indicated by the numbers with black circles without) are written. That is, as shown in FIG. 8B, the longitudinal acceleration data (data indicated by a white circled number without a ') is continuously written in the first acceleration data storage area 134 of the waveform memory 13, but the waveform memory 13 The second acceleration data storage area 136 is overwritten with the left-right acceleration data (data indicated by black circled numbers without ').

The CPU 11 also writes longitudinal acceleration data and lateral acceleration data (steps S116, 1).
Each time step 18) is performed, it is determined whether the elapsed time t of the internal timer exceeds a preset time T (see FIG. 4) (step S120).

After that, when the elapsed time t of the internal timer exceeds the set time T, the process proceeds to step S124 by the determination in step S120, the CPU 11 finishes writing the longitudinal acceleration data, and only writes the lateral acceleration data. (Step S118). Since the waiting time in step S126 for writing the lateral acceleration data is the same as in step S122 (2 × t0),
It is performed almost every time (2 × t0) same as before. Then, this time, the lateral acceleration data is written (step S
Every time step 118) is performed, it is determined whether the elapsed time t of the internal timer exceeds the sum of the set time T and the time difference t1, that is, the time (T + t1) (step S124).

After that, when the elapsed time t of the internal timer exceeds the time (T + t1), the CPU 11 causes the waveform memory 13
The code of the form is written in the code storage area 130 (step S128), and the first writing process ends.
That is, in this case, the two safing sensors are both turned on, and further the front impact safing sensor 14 is turned on first, which corresponds to the form I shown in FIG. 2 and as shown in C of FIG. Then, the code “0111” is written in the code storage area 130.

Next, the second writing process (step S200) of FIG. 3 will be described with reference to FIGS. 7 and 8.
Since it is essentially the same as the first writing process, only the differences will be briefly described. In other words, since the side impact safing sensor 24 is already turned on in the second writing process (step S20), as shown in F of FIG. 8, the first and second acceleration data storage areas of the waveform memory 13 are stored. Thirteen
The lateral acceleration data is alternately written in 4, 136 (step S206). That is, in the first acceleration data storage area 134, the data indicated by simple black circled numbers are
In the second acceleration data storage area 136, data indicated by black circled numbers with '(apostrophe) are written. After that, safing sensor 1 for frontal collision
When 4 is not turned on (step S204), the lateral acceleration data is continuously written in the first and second acceleration data storage areas 134 and 136, as shown by I in FIG. Therefore, in this case, only the side collision safing sensor 24 is turned on, which corresponds to the form IV shown in FIG. 2, so when the elapsed time t exceeds the set time T (step S208). As shown by J in FIG. 8, the code “0001” is written in the code storage area 130 (step S212).

However, the safing sensor 14 for frontal collision is used.
Is turned on (step S204), as shown in G of FIG. 8, the side impact safing sensor 24 is turned on and the front impact safing
The time difference t1 until the sensor 14 is turned on is written (step S214). Then, the left-right acceleration data (data indicated by black circled numbers without ') is continuously written in the first acceleration data storage area 134 (step S216), but the second acceleration data storage area 1
Longitudinal acceleration data (data indicated by white circled numbers without ') is overwritten on 36 (step S218). So in this case two safing
Since both sensors are turned on and the side impact safing sensor 24 is turned on first, which corresponds to the form II shown in FIG. 2, when the elapsed time t exceeds the set time (T + t1). (Step S224) As shown in H of FIG. 8, the code "0110" is written in the code storage area 130 (step S228).

In the above writing process, the detected acceleration data is written into the waveform memory 13 at any time. However, the detected acceleration data is once stored in the CPU 11.
Alternatively, the waveform may be pooled in the waveform memory 13 and then written to the waveform memory 13 at once. Such a writing process will be described next.

FIG. 9 is a flow chart showing another example of the first write processing in FIG. 3, and FIG. 10 is a second flow chart in FIG.
It is a flowchart which shows the other example of a writing process. Now, the first writing process shown in FIG. 9 will be described. As shown in FIG. 9, when the first writing process is started, C
PU11 sets the time t of the internal timer (not shown) of CPU11 to zero (step S152). And C
The PU 11 pools the longitudinal acceleration data detected by the longitudinal acceleration sensor 12 in the internal memory (not shown) of the CPU 11 until the side impact safing sensor 24 is turned on (step S154) (step S15).
6). Since the waiting time in step S160 is t0, pooling to the internal memory is performed almost every time t0. In addition, the CPU 11 determines whether or not the elapsed time t of the internal timer exceeds the preset time T every time the longitudinal acceleration data is pooled (step S156) (step S158).

By the time the elapsed time t of the internal timer exceeds the set time T, the side impact safing sensor 24 is activated.
If is not turned on, when the elapsed time t exceeds the set time T, the CPU 11 causes the code storage area 1 of the waveform memory 13 to
The code of the form is written in 30, and the longitudinal acceleration data pooled in the internal memory is stored in the waveform memory 13 at once.
First and second acceleration data storage areas 134, 136 of
(Step S162), and then the first writing process ends. As a result, data is written in the waveform memory 13 as indicated by E in FIG.

On the other hand, before the elapsed time t of the internal timer exceeds the set time T, the side impact safing sensor 24 is turned on.
Then, the process proceeds to step S164 according to the determination in step S154 in FIG. In step S164, the CPU 11
Calculates the time difference t1 by referring to the elapsed time t of the internal timer and pools it in the internal memory. Then, the CPU 11
The longitudinal acceleration data detected by the longitudinal acceleration sensor 12 is pooled in the internal memory (step S166), and the lateral acceleration data detected by the lateral acceleration sensor 22 is also pooled in the internal memory (step S16).
8). The waiting time in step S172 is
It is twice as large as 160 (2 × t0), and pooling to the internal memory is performed almost every time (2 × t0).

The CPU 11 also pools the longitudinal acceleration data and the lateral acceleration data (steps S166, 16).
Each time 8) is performed, it is determined whether the elapsed time t of the internal timer has exceeded a preset time T (step S1).
70).

Thereafter, when the elapsed time t of the internal timer exceeds the set time T, the process proceeds to step S174 by the determination in step S170, the CPU 11 finishes the pooling of the longitudinal acceleration data in the internal memory, and the pooling of the lateral acceleration data. Only continues (step S16)
8). Then, every time the lateral acceleration data is pooled (step S168), the elapsed time t of the internal timer is the sum of the set time T and the time difference t1, that is, the time (T + t).
It is determined whether or not 1) is exceeded (step S17).
4).

After that, when the elapsed time t of the internal timer exceeds the time (T + t1), the CPU 11 causes the waveform memory 1
No. 3 in the code storage area 130, the time difference t1 pooled in the internal memory is written in the time difference storage area 132, and the pooled longitudinal acceleration data is stored in the first acceleration data storage area 134. Data is stored in the second acceleration data storage area 136.
Then, the writing is performed at once (step S178), and then the first writing process is ended. As a result, the waveform memory 13
The data is written in the area C as shown in FIG.

Next, the second write processing shown in FIG. 10 will be described, but since it is essentially the same as the first write processing shown in FIG. 9, only the differences will be briefly described. That is, in the second writing process, the side impact safing sensor 24 has already been turned on (step S2 in FIG. 3).
0), the CPU 11 pools the lateral acceleration data in the internal memory (step S256). If the safing sensor 14 for front-end collision is not turned on even after that (step S254), when the elapsed time t exceeds the set time T (step S256), the CPU 11 causes the waveform memory 1 to operate.
3, the longitudinal acceleration data pooled in the internal memory is written to the waveform memory 13 at once (step S262), and then the second writing process is ended. As a result, the waveform memory 13 is stored in FIG.
The data is written as indicated by J in FIG.

However, the front safing sensor 14
If is turned on (step S254), the CPU 11
Pools the time difference t1 in the internal memory (step S2).
64). Then, the lateral acceleration data is continuously pooled in the internal memory (step S266), and the longitudinal acceleration data is also pooled (step S268). Finally, when the elapsed time t exceeds the set time (T + t1) (step S274), the CPU 11 causes the waveform memory 13
And the time difference t1 pooled in the internal memory, the longitudinal acceleration data and the lateral acceleration data are written to the waveform memory 13 at one time (step S
278) and then the second writing process ends. As a result, data is written in the waveform memory 13 as indicated by H in FIG.

As described above, in the present embodiment, the front impact ECU 10 and the side impact ECU 20 are connected by the data line 30, and the lateral acceleration detected by the side impact safing sensor 24 is detected. ECU2 for side impact data
0 to the front collision ECU 10, and the longitudinal acceleration sensor 1
Since the waveform memory 13 is written together with the longitudinal acceleration data detected in step 2,
Only one piece is needed, and the number of parts can be reduced.

When both the longitudinal acceleration data and the lateral acceleration data are written in the waveform memory 13, the time point when the front collision safing sensor 14 is turned on and the time point when the side impact safing sensor 24 is turned on. Time difference t1
Since the waveform memory 13 is also written in the waveform memory 13, by reading the time difference t1 later, the temporal correspondence relationship between the written longitudinal acceleration data and lateral acceleration data can be easily grasped, and a comprehensive Analysis can be performed. That is, for example, when a vehicle collision such as an oblique collision occurs, it is possible to analyze the time difference between the deployment of the airbag for frontal collision and the deployment of the airbag for side collision, or there is a secondary collision. When the vehicle rolls after the front collision and the side surface of the vehicle collides with the pole, the collision can be analyzed.

When only one of the longitudinal acceleration data and the lateral acceleration data is written in the waveform memory 13, the sampling time interval is reduced to about 1/2 and the first and second waveform data in the waveform memory 13 are written. Since the data is written in both of the acceleration data storage areas 134, 136, the data amount should be about twice the data amount of one acceleration data when both the longitudinal acceleration data and the lateral acceleration data are written. You can Therefore,
Since it is possible to store a finer change in acceleration over time, more detailed analysis can be performed. Even if the number of bits of the acceleration data at the time of writing is increased, the data amount of the acceleration data to be written can be increased. In such a case, a more accurate value for acceleration can be stored.

In the acceleration data writing process of FIG. 3 described above, the longitudinal acceleration data is first written or pooled by turning on the safing sensor 14 for a front collision, and the lateral acceleration data is collided with a side collision. Writing or pooling was performed for the first time when the safing sensor 24 for use turned on. However, both the longitudinal acceleration data and the lateral acceleration data may be written or pooled when either one of the two safing sensors is turned on. Such a writing process will be described next.

FIG. 11 is a flow chart showing another example of the acceleration data writing process in the protective device ECU shown in FIG. 1, and FIG. 12 is a time chart of the acceleration detected by the longitudinal acceleration sensor 12 and the lateral acceleration sensor 22 of FIG. It is a wave form diagram which shows change. In FIG. 12, (a) shows a temporal change in the longitudinal acceleration detected by the longitudinal acceleration sensor 12, and (b) shows a temporal change in the lateral acceleration detected by the lateral acceleration sensor 22.

As shown in FIG. 11, the CPU 11 includes a front-collision safing sensor 14 and a side-collision safing sensor.
It is determined whether or not the sensor 24 is turned on (step S
300, 302). When either one of the front-collision safing sensor 14 and the side-collision safing sensor 24 is turned on, the process proceeds to step S304, and the CPU 11 causes the CPU 11 to use an internal timer (not shown) of the CPU 11.
Is set to zero (step S304), and the writing of the acceleration data to the waveform memory 13 is started. At this time, the CPU 11 writes both the longitudinal acceleration data detected by the longitudinal acceleration sensor 12 and the lateral acceleration data detected by the lateral acceleration sensor 22 (step S306). Since the waiting time in step S310 is t0 ′, the writing of these data is performed almost every time t0 ′. That is, in the first and second acceleration data storage areas 134 and 136 of the waveform memory 13, longitudinal acceleration data (data indicated by white circled numbers) and lateral acceleration sampled at intervals of approximately time t0 ′ shown in FIG. Data (data indicated by black circled numbers) is written. Further, the CPU 11 determines whether or not the elapsed time t of the internal timer exceeds the preset time T (see FIG. 12) every time data is written (step S308) (step S308), and the internal timer When the elapsed time t exceeds the set time T, the process ends.

Also in the writing process shown in FIG. 11, instead of writing the detected acceleration data in the waveform memory 13 as needed, the detected acceleration data is temporarily pooled in the CPU 11 as in the case of FIGS. 9 and 10. After that, the waveform memory 13 may be written at once. Such a writing process will be described next.

FIG. 13 is a flowchart showing another example of the acceleration data writing process in the ECU for the protection device shown in FIG. As shown in FIG. 13, when either one of the front collision safing sensor 14 and the side collision safing sensor 24 is turned on (steps S400 and 402), the CPU 11 has an internal timer of the CPU 11. The time t (not shown) is set to zero (step S4
04), the pooling of acceleration data to the internal memory (not shown) of the CPU 11 is started. At this time, the CPU 11
Both longitudinal acceleration data and lateral acceleration data are pooled (step S406). Since the waiting time in step S410 is t0 ′ for the pool of these data,
It is performed almost every time t0 '. In addition, the CPU 11 determines whether or not the elapsed time t of the internal timer exceeds the set time T each time the data is pooled (step S408) (step S408). After that, when the elapsed time t of the internal timer exceeds the set time T, the CPU 11 writes both the longitudinal acceleration data and the lateral acceleration data from the internal memory pool into the waveform memory 13 at one time (step S412), and ends the process. .

According to the writing process shown in FIG. 11 or FIG. 13, both the longitudinal acceleration data and the lateral acceleration data are stored in the waveform memory 13 from the time when either one of the two safing sensors is turned on. Since the data is written or written after being pooled in the internal memory, the temporal correspondence between the written longitudinal acceleration data and lateral acceleration data becomes clear. Therefore, the acceleration data can be read out later for comprehensive analysis.

In the above description, the waveform memory 13 is not particularly mentioned, but since it is necessary to read the acceleration data stored in the waveform memory 13 after a vehicle collision, it is stored until it is read. Data must be kept stable. Therefore, for example, a memory that is electrically backed up, a programmable ROM capable of writing data, an erasable programmable ROM, or the like may be used. The waveform memory 13 may be incorporated in the side collision ECU 20, but since the side collision ECU 20 is mounted inside the door panel of the vehicle, it is more easily destroyed than the front collision ECU 10 mounted inside the floor tunnel during a vehicle collision. . Therefore, as in this embodiment, the waveform memory 13 is used for the front collision ECU.
It is more reliable to store the acceleration data in the built-in 10.

In the embodiment described above, C
PU11 plays a central role in turning on the safing sensor
Although the ON / OFF determination and the writing of the acceleration data into the waveform memory 13 (or the writing after the pooling to the internal memory) have been performed, the CPU 21 may take the lead in performing these processes, or the two cooperate. You may go.

In the above embodiment, the acceleration data from the time when the safing sensor is turned on is written in the waveform memory 13, but the data before a predetermined time from the time when the safing sensor is turned on are also written. You may do it. For example, the acceleration data is constantly written in the waveform memory 13 and updated one after another, and when the safing sensor is turned on, the data for a predetermined time before that time is also left in the waveform memory 13, and The acceleration data after the time point may be further written.

In the above-described embodiment, the acceleration data writing process is performed when the safing sensor is turned on, but the present invention is not limited to this. For example, the acceleration data may be written when the acceleration detected by the longitudinal acceleration sensor 12 or the lateral acceleration sensor 22 exceeds a preset value. Further, another sensor for detecting an impact applied to the vehicle may be provided, and the writing process may be performed when the detected impact exceeds a preset value.

[0064]

According to the first aspect of the invention, when the data of both the first and second accelerations is written, the information representing the temporal correspondence between the two is also written. Therefore, by reading the information at the time of analysis, it is possible to easily grasp the temporal correspondence relationship between the written first and second acceleration data, and to perform comprehensive analysis. .

According to the second aspect of the present invention, when only the data of one of the detected first and second accelerations is written in the storage means, the data amount is set to the data of both the first and second accelerations. It is set larger than the data amount of one data when writing. Therefore, since the amount of data to be written is large, it is possible to store a finer change with respect to a temporal change of the acceleration as compared with the case of writing both the first and the second acceleration data, and thus a more detailed analysis can be performed. It can be carried out.

In the invention described in claim 3, the first and second aspects are provided.
When a shock of a predetermined value or more is applied to any one of the directions, the first and second directions are not limited to the direction in which the shock is applied.
Since the acceleration data when the impact is applied is written in both directions, the temporal correspondence between the written first and second acceleration data becomes clear. Therefore, during the analysis, it is possible to read the acceleration data and perform a comprehensive analysis.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a protective device ECU including an acceleration detection device according to an embodiment of the present invention.

[FIG. 2] ON / O of the safing sensor in FIG.
FIG. 6 is an explanatory diagram for explaining a difference in a writing form of acceleration data according to an FF state and the like.

FIG. 3 is a flowchart showing an example of acceleration data writing processing in the protective device ECU shown in FIG. 1.

4 is a waveform diagram showing a temporal change in acceleration detected by a longitudinal acceleration sensor 12 and a lateral acceleration sensor 22 of FIG.

5 is an explanatory diagram schematically showing the division of storage areas in the waveform memory 13 of FIG.

6 is a flowchart showing an example of a first writing process in FIG.

7 is a flowchart showing an example of a second writing process in FIG.

8 is an explanatory diagram showing a transition of data written in the waveform memory 13 of FIG. 5 by the write processing of FIGS. 6 and 7. FIG.

9 is a flowchart showing another example of the first writing process in FIG.

FIG. 10 is a flowchart showing another example of the second write processing in FIG.

11 is a flowchart showing another example of acceleration data writing processing in the protective device ECU shown in FIG.

12 is a waveform diagram showing a temporal change in acceleration detected by a longitudinal acceleration sensor 12 and a lateral acceleration sensor 22 of FIG.

13 is a flowchart showing another example of acceleration data writing processing in the protective device ECU shown in FIG.

[Explanation of symbols]

10 ... ECU for frontal collision 11 ... CPU 12 ... longitudinal acceleration sensor 13 ... Waveform memory 14 ... Safing sensor for frontal collision 15 ... FET 20 ... ECU for side impact 21 ... CPU 22 ... Left-right acceleration sensor 24 ... Safing sensor for side impact 25 ... FET 30 ... Data line 40 ... Squib for frontal collision 50 ... Squib for side impact 130 ... Code storage area 132 ... Time difference storage area 134 ... First acceleration data storage area 136 ... Second acceleration data storage area

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-55993 (JP, A) JP-A-7-81516 (JP, A) JP-A-6-127332 (JP, A) JP-A-7- 2049 (JP, A) Actual Kaihei 5-65706 (JP, U) Japanese Patent Publication 5-64746 (JP, B2) International Publication 96/027514 (WO, A1) (58) Fields investigated (Int.Cl. ⁷⁾ , DB name) B60R 21/16-21/32 B60R 22/46-22/48 G01P 15/00

Claims (5)

(57) [Claims] 1. An acceleration detection device mounted on a vehicle, comprising: a first acceleration sensor for detecting a first acceleration applied to the vehicle in a first direction; and a first acceleration sensor for the vehicle. A second acceleration sensor for detecting a second acceleration applied in a second direction different from the direction; storage means having a plurality of storage areas; and a predetermined value or more in the first direction with respect to the vehicle. When an impact is applied, a plurality of data of the first acceleration detected when the impact is applied are written in the storage means along the time axis, and are written in the second direction with respect to the vehicle. When an impact of a predetermined value or more is applied, a plurality of writing means for writing the second acceleration data detected when the impact is applied to the storage means along a time axis, and The writing means detects the When data of both the first and second accelerations is written in the storage means, the first acceleration data and the second data to be written are written.
An acceleration detecting device, characterized in that information representing a temporal correspondence with the acceleration data is also written. 2. An acceleration detecting device mounted on a vehicle.
Te, detects the first acceleration applied in a first direction relative to said vehicle
A first acceleration sensor that emits and a second direction different from the first direction with respect to the vehicle
Second acceleration sensor for detecting a second acceleration applied to the
A storage means having a plurality of storage areas, and an impact of a predetermined value or more on the vehicle in the first direction.
If added, it will be detected when the impact is applied.
A plurality of the first acceleration data along the time axis
Writing in the storage means, the second direction with respect to the vehicle
If a shock greater than the specified value is applied to the
The data of the second acceleration detected when
Writing means for writing a plurality of pieces in the storage means along an axis
When, wherein the writing means, said detected first and second pressure
When writing both speed data to the storage means
Is the written first acceleration data and the second acceleration data.
Information that represents the temporal correspondence with the acceleration data of
Writes the same time, the writing unit, when only one of the data of the detected first and second acceleration written in the storage means, the data amount of the data to be written, the first And the second acceleration, the acceleration detecting device is characterized in that it is made larger than the data amount of one data when writing the data. 3. An acceleration detecting device mounted on a vehicle, comprising: a first acceleration sensor for detecting a first acceleration applied to the vehicle in a first direction; and a first acceleration sensor for the vehicle. A second acceleration sensor that detects a second acceleration applied in a second direction different from the direction, a storage unit having a plurality of storage areas, and one of the first and second directions with respect to the vehicle. When an impact greater than or equal to a predetermined value is applied to one of them, a plurality of data of both the first and second accelerations detected when the impact is applied are stored in the storage means. An acceleration detecting device, comprising: 4. The acceleration detecting device according to claim 1, 2, or 3, wherein the first direction is a front-back direction of the vehicle and the second direction.
Is the left-right direction of the vehicle, the first acceleration sensor and the storage means are arranged near a floor tunnel of the vehicle, and the second acceleration sensor is arranged inside a door panel of the vehicle. An acceleration detecting device characterized by: 5. The acceleration detecting device according to claim 1 or 2.
The writing means is arranged in the first direction with respect to the vehicle.
If a shock greater than the specified value is applied to the
From the first time when the impact of
The data of the first acceleration detected during
Along writing the plurality prior Symbol storage means, with respect to the vehicle
When an impact of a predetermined value or more is applied in the second direction,
Is a predetermined value from at least the second time when the impact is applied.
Of the second acceleration detected during the period
Write a plurality of data in the storage means along the time axis
At the same time, the writing means is configured to detect the first and second applied voltages.
When writing both speed data to the storage means
Is the first information as the information indicating the temporal correspondence.
Write the information that represents the time difference between the second time and
An acceleration detection device characterized by being embedded.