JPH0858502A - Controller for vehicle safety device - Google Patents

Abstract

PURPOSE: To provide a controller for the vehicle safety device capable of securing an assured action not only at the time of head-on collision of a vehicle but also at the time of declinational collision by detecting the ultrasonic wave generated at the time of vehicle collision and actually changing the detected sensitivity of an acceleration detection means at the time of detecting the ultrasonic wave. CONSTITUTION: Acceleration at the time of vehicle collision is detected by an acceleration sensor 1. Whether or not the vehicle speed enumerated by integrating the detected acceleration has exceeded the reference value is judged by CPU 3. A squib 10 is electrified in accordance with the result of the judgment and a vehicle safety device, for example, an air bag device is actuated. In this case, ultrasonic wave generated at the time of vehicle collision is detected by an ultrasonic wave sensor 2. When ultrasonic wave is detected, sensitivity detected by the acceleration sensor 1 is actually changed. In other words, the reference value of CPU 3 is changed. Thus a controller for vehicle safety device capable of securing an assured action not only at the time of head-on collision of a vehicle but also at the time of declinational collision is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle safety device control device for controlling the operation of a so-called airbag device as a vehicle safety device, and more particularly to a device for improving the operation timing of the airbag device.

[0002]

2. Description of the Related Art Heretofore, as a control device for a vehicle safety device of this kind, which is publicly known or well known, for example, as disclosed in Japanese Patent Laid-Open No. 59-8574, an acceleration sensor and an acceleration sensor There is a configuration in which an integrating circuit that integrates the output signal of the sensor is provided, the speed of the vehicle is calculated, and the calculated vehicle speed is used as judgment data for deciding whether or not to operate the airbag device.

In such a vehicle safety device control device, the acceleration sensor may be installed at a plurality of locations or at a specific location. As in the former case, the sensors are installed at a plurality of locations. Whereas the case of performing acceleration detection is called the multi-point sensor method,
The latter case where a sensor is installed at one location to detect acceleration may be referred to as a single point sensor method. Many of the vehicle safety device control devices currently in use employ a single point sensor system.

[0004]

[Problems to be Solved by the Invention]
It is known that the point sensor method is generally advantageous for a vehicle body having a high rigidity on the front surface of the vehicle body. This is because if the rigidity of the front surface of the vehicle body is weak, the impact force generated at the time of a collision is weak, and therefore, the time when the acceleration sufficient to operate the airbag device is detected is delayed, and the driver is However, when the rigidity of the front of the vehicle body is high, the acceleration sensor detects sufficient signals at the initial stage of the collision, and the airbag is properly deployed. This is because

A vehicle destruction process suitable for such a single point sensor system in a vehicle collision is as follows.
For example, as shown in FIG. 4, in the case of a so-called FF vehicle in which the engine 20 is mounted in the front part of the vehicle and the front wheels are driven, the following destruction mode is considered to be ideal. Note that, in FIG. 4, the ECU is an electric control unit for controlling the operation of the airbag device and the like.

That is, if the vehicle collides head-on with an obstacle 23 such as another vehicle at a high speed under the condition that the bumper 21 has a high rigidity, the bumper 21 absorbs an appropriate amount of shock while the bumper 21 is absorbed. It is in a form in which a so-called crushable zone 22 is gradually compressed between the engine block and a certain engine block, and finally the engine block is destroyed by a strong impact.

It is known that in such a collision mode, changes in acceleration are roughly classified into three stages, as shown in FIG. That is, at first, deceleration (negative acceleration) due to the impact force of the bumper 21 occurs, a point of maximum deceleration (point of maximum absolute value of acceleration in the negative region) appears, and after that point, deceleration again occurs. Area A (see Fig. 5) where the deceleration decreases, and area B where the deceleration fluctuates slightly, and then the deceleration changes greatly. A point appears, and the deceleration decreases thereafter.

However, since the destruction process as described above differs depending on the vehicle structure, the change in acceleration also differs depending on the vehicle structure. Therefore, the vehicle speed is obtained from this acceleration, and this vehicle speed is specified. In the conventional device that operates the airbag device when the reference value is exceeded, the reference value should be set so that the airbag device can be operated in good timing regardless of the vehicle structure. There was a problem that it was difficult.

The present invention has been made in view of the above circumstances, and provides a control device for a vehicle safety device that can obtain a reliable operation regardless of the difference in vehicle structure.
Another object of the present invention is to provide a vehicle safety device control device capable of ensuring reliable operation not only in a head-on collision but also in a declination collision.

[0010]

According to a first aspect of the present invention, there is provided a vehicle safety device control device including an acceleration detecting means for detecting an acceleration at the time of a collision of a vehicle, and an acceleration detected by the acceleration detecting means. And a vehicle safety control means for controlling the operation of the vehicle safety device based on the determination result of the operation determination means. In the device control device, an ultrasonic wave detecting means for detecting an ultrasonic wave generated at the time of collision of a vehicle, and a detection sensitivity of the acceleration detecting means when the ultrasonic wave is detected by the ultrasonic wave detecting means. And a sensitivity changing means for changing the sensitivity. In particular, the sensitivity changing means is preferably one that changes the reference value in the motion determining means.

A control device for a vehicle safety device according to a third aspect of the present invention is calculated by integrating acceleration detection means for detecting acceleration at the time of a vehicle collision and acceleration detected by the acceleration detection means. In a control device for a vehicle safety device, which comprises an operation determination means for determining whether or not the vehicle speed exceeds a reference value, and which controls the operation of the vehicle safety device based on the determination result of the operation determination means, An ultrasonic wave detecting means for detecting an ultrasonic wave generated at the time of a vehicle collision, and a sensitivity changing means for substantially changing the detection sensitivity of the acceleration detecting means for a certain period of time according to the detection result of the ultrasonic wave detecting means. And are provided.

Particularly, the sensitivity changing means is preferably adapted to change the reference value in the operation judging means over the predetermined period when the ultrasonic wave is detected by the ultrasonic wave detecting means for a predetermined period. . Further, it is preferable that the predetermined period in the sensitivity changing means corresponds to a period in which the front portion of the vehicle from the bumper portion to the engine block is destroyed during a frontal collision. Furthermore, it is preferable that the sensitivity changing means changes the reference value in a direction in which it is easier to determine that the vehicle speed exceeds the reference value.

[0013]

In the vehicle safety device control apparatus according to the present invention, when the ultrasonic wave generated when the vehicle collides is detected by the ultrasonic wave detecting means, the sensitivity changing means changes the sensitivity of the acceleration detecting means. Is substantially changed, that is, the sensitivity of the sensor itself is changed, or the sensitivity of the sensor itself is changed by changing the threshold value when processing the output signal while maintaining the sensitivity of the sensor itself. By making the state equivalent to the changed state and substantially changing the sensitivity, it is possible to more accurately determine whether the vehicle speed obtained by integrating this acceleration exceeds a predetermined value. It is a thing.

Particularly, in the control device for a vehicle safety device according to the second aspect of the present invention, the reference for determining whether or not the vehicle speed obtained by integrating the detected acceleration exceeds a reference value. By changing the value, the detection sensitivity of the acceleration detecting means is substantially changed, and the airbag can be deployed at an appropriate time.

In the vehicle safety device control device according to the third aspect of the present invention, when the ultrasonic wave generated when the vehicle collides is detected by the ultrasonic wave detecting means, the impression changing means operates the acceleration detecting means. The sensitivity has changed substantially, that is,
By changing the so-called sensitivity of the sensor itself, or while maintaining the sensitivity of the sensor itself, by changing the value corresponding to the threshold value when processing the output signal, it is assumed that the sensitivity of the sensor itself is equivalent to a changed state, By substantially changing the sensitivity, and further by substantially changing the sensitivity according to the detection condition of the ultrasonic wave, the airbag is deployed at a more accurate time.

Particularly, in the vehicle safety device control device according to the present invention, it is necessary to determine whether the vehicle speed obtained by integrating the detected acceleration exceeds a reference value. By changing the reference value while the ultrasonic wave is being detected for a predetermined period, the detection sensitivity of the acceleration detecting means is substantially changed, and the airbag can be deployed at a more accurate time. .

Further, in the vehicle safety device control device according to the present invention, the period during which the detection sensitivity of the acceleration detecting means is substantially changed from the bumper portion to the engine block during a frontal collision. By setting the period in which the front portion of the vehicle is destroyed, that is, the period corresponding to the so-called crushable zone destruction time, it is possible to obtain an appropriate operation at the time when the airbag needs to be deployed.

Further, in the vehicle safety device control apparatus according to the present invention, the reference value when the vehicle speed is judged by the operation judging means by the sensitivity changing means is such that the vehicle speed exceeds the reference value. It is changed to a value that makes it easier to judge that it has been decided that it is possible to eliminate the delay of the conventional judgment timing due to the difference in acceleration change due to the difference in vehicle body structure, and to perform an appropriate operation when the airbag needs to be deployed. It is something that can be obtained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a vehicle safety device control device according to the present invention will be described below with reference to FIGS. Here, FIG. 1 is a configuration diagram showing a configuration of a main part of a vehicle safety device control device in the present embodiment, FIG. 2 is a flowchart showing a procedure of operation control by a CPU, and FIG. FIG. 3A is a characteristic diagram showing a change in acceleration at the time of a collision, and FIG. 3B is a characteristic diagram showing a change in vehicle speed obtained from FIG. FIG. 3C is a characteristic diagram showing changes in ultrasonic waves that occur during a collision. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.

First, the present apparatus includes an acceleration sensor 1 as an acceleration detecting means, an ultrasonic sensor 2 as an ultrasonic detecting means, a CPU 3, a squib test circuit 4, an ignition circuit 5, and a clamp circuit 6. The power supply circuit 7 is a main component. The acceleration sensor 1 may be one that has been conventionally used in this type of device, and, for example, the resistance value of the semiconductor gauge may change according to the strain caused by the generation of acceleration in the gauge formed of a semiconductor. It is preferable to use a semiconductor-type acceleration sensor that uses a sensor or a piezoelectric acceleration sensor that uses a piezoelectric element such as a crystal with a weight attached so that acceleration is applied to the piezoelectric element to obtain a piezoelectric signal due to the piezoelectric effect. is there.

The acceleration sensor 1 shown in FIG. 1 also includes a so-called drive circuit portion, and when the apparatus starts, the CP
A sensor test signal can be input from U3, and the output signal at that time enables the CPU 3 to check whether the acceleration sensor 1 is normal or not.

The ultrasonic sensor 2 is for detecting an ultrasonic wave (details will be described later) generated when a vehicle in which the present apparatus is mounted is destroyed due to a collision, and is made of, for example, piezoelectric ceramics. Is preferred. Since the device according to the present embodiment adopts a so-called single point sensor system, the acceleration sensor 1 and the ultrasonic sensor 2 described above are attached at the same place, and specifically, for example, so-called gear change is performed. In a floor shift type vehicle, it is arranged on the front side of the change lever (on the front side of the vehicle body).

The CPU 3 includes a storage unit, an arithmetic unit, an analog
This is a so-called one-chip microcomputer in the form of an IC having a digital conversion unit and the like inside. In FIG. 1, C
The portion marked "A / D" in PU3 means an analog-digital conversion input terminal (hereinafter referred to as "A / D input terminal"), and the analog signal input to this terminal is in the CPU3. The analog-to-digital converter (not shown) converts the signal into a digital signal for subsequent processing.

The CPU 3 inputs the sensor output signals of the acceleration sensor 1 and the ultrasonic sensor 2 by executing a control program as described later, and energizes the squib 10 at an appropriate time based on these sensor output signals. As a result, an air bag device (not shown) as a vehicle safety device is activated.

In this embodiment, the output terminals of the acceleration sensor 1 and the ultrasonic sensor 2 are the CPUs, respectively.
3 is connected to the A / D input terminal. The squib test circuit 4 is an energizing circuit mainly composed of the transistor 8. That is, in the squib test circuit 4 of this embodiment, the base of the NPN transistor 8 is the CPU.
3 is input to the I / O terminal of the
The emitter is grounded, and the collector is connected to one end of the heater wire 10a of the squib 10 via the resistor 9a. The test voltage V (V <VDD) is applied to the other end of the heater wire 10a through the resistor 9b.

Then, at the base of the transistor 8, CP
When a pulse signal for turning on the transistor 8 is applied from the I / O terminal of U3, the heater wire 1 of the squib 10
A test current smaller than that in the actual operation, which is limited by the resistor 9b connected to the other end of 0a and the resistor 9a connected to the collector of the transistor 8, flows.

On the other hand, a resistor 11 is provided at both ends of the heater wire 10a.
It is connected to the other two A / D input terminals of the CPU3 via a and 11b, and the heater wire 10a is energized by the CPU3.
Can be monitored at. The clamp circuit 6 is connected to the two A / D input terminals of the CPU 3 to which both ends of the heater wire 10a are connected.
The surge current, etc., which accompanies the energization of the heater wire 10a, which may cause the destruction of the heater, is removed.

The other end of the heater wire 10a of the squib 10 is connected to a power supply section 13 via a safing switch (abbreviated as "safing SW" in the figure) 14, and the safing switch 14 In the closed state, the operating voltage VDD is applied from the power supply unit 13.

The safing switch 14 is a kind of acceleration sensor, and its contact is normally in the open state (OF
Although it is F), it becomes a closed state (ON) when a deceleration of a certain amount or more is applied, and a mechanical acceleration sensor is mainly used. In addition, this safing switch 14 also
The acceleration sensor 1 and the ultrasonic sensor 2 are installed at the same place.

The ignition circuit 5 is connected to the heater wire 10a of the squib 10 when it is determined that the heater wire 10a of the squib 10 is energized by the execution of a program in the CPU 3, as will be described later, that is, when the airbag is expanded. In this embodiment, NPN type M
The gate of OS FET12 is the I / O terminal of CPU3,
The drain is connected to one end of the heater wire 10a of the squib 10 (the side to which one end of the resistor 9a is connected), and the source is connected to the ground.

By applying a pulse signal as an ignition output from the I / O terminal to the gate of the MOS FET 12, the MOS FET 12 is rendered conductive, and moreover, it is connected to the heater wire 10a of the squib 10 in series. When the switching switch 14 is closed, the heater wire 10a and the MOS FET 12 are energized.

The power supply circuit 7 is for converting a DC voltage (for example, 12 V) applied from the outside into a DC voltage suitable for the operation of the CPU 3 and the like. In this embodiment,
For example, the power supply unit 13 is mainly configured by using an integrated circuit that stabilizes an input DC voltage called a three-terminal regulator and converts the input DC voltage into a voltage different from the input voltage. The power supply unit 13 of this embodiment can output the input DC voltage as the voltage Vcc for the CPU 3 and the voltage VDD when the squib 10 is in operation.

Next, referring to FIG. 2 and FIG. 3, the CPU
A series of controls executed by No. 3 will be described. First, the basic idea of the collision determination processing in this device will be described with reference to FIG. For example, in the case of a high-speed frontal collision of a vehicle, as shown in FIG. 3A, the acceleration is decelerated by the impact force of the bumper portion, so that the deceleration gradually increases (in the negative acceleration region, Area a showing a change such that the absolute value reaches the maximum value, and then the deceleration becomes smaller (toward the positive acceleration area), and the car body is compressed and destruction progresses to the engine block. The maximum value that the deceleration increases again as the engine block is destroyed and the region b that shows a change in which the deceleration changes periodically as it goes down (so-called destruction of the crushable zone). It is known that it is roughly divided into a region c which shows a change such that the deceleration becomes smaller after that.

Here, the time t1 which is the boundary point between the area A and the area B is the time at which the expansion of the airbag is generally required. Although there are some differences depending on the vehicle body structure, for example, 30 ms to 30 ms. It takes a value of about 40 ms. At time t2, which is the boundary point between region b and region c.
Is the time when the so-called crushable zone destruction ends and the engine block destruction begins. Further, time t3 corresponds to the time when the destruction of the engine block is almost completed.

The speed calculation value ΔV as the vehicle speed obtained by integrating the acceleration of such a change is shown in FIG.
As shown in (b), the absolute value gradually increases in the negative region with the passage of time.
Whether or not the air bag device is operated, that is, whether or not the squib 10 is energized is determined by the calculated speed value ΔV.
In that it is performed by determining whether is greater than or equal to a predetermined value,
This device is similar to the conventional device.

Conventionally, this predetermined value is a predetermined time from the start of the collision in consideration of the result calculated from simulation experiments etc. in addition to the deployment start time of the airbag which is generally required from the viewpoint of ensuring the safety of the driver. It was set to a value that would allow the airbag to be deployed in the vicinity. In the example of FIG. 3, the deployment start time of the airbag is from around time t1 to time t2.

However, in the case of a declination collision, the acceleration change, especially in the initial stage of the collision, that is, the acceleration change in the area (a) of FIG. 3A, is a frontal collision as shown by the dotted line in FIG. The deceleration tends to be larger than that of time. Therefore, if the operation start of the airbag device is judged based on whether or not the calculated speed value ΔV exceeds a single constant value, the airbag is suitable for a frontal collision but is not suitable for a declination collision. Even if the operation of the device is too fast or, conversely, it is suitable for a declination collision, it may be delayed for a frontal collision or an inconvenient operation may not be obtained.

As a result of intensive research on various phenomena occurring in the vehicle body at the time of collision, the present inventor has found that ultrasonic waves appear at the time of collision as shown in FIG. 3 (c).
That is, the present inventor has found that this ultrasonic wave always appears in frontal collision and declination collision even if there is a difference in frequency components. In the past, during so-called crushable zone destruction (see FIG. 3). In the example, it was difficult to set the proper operation of the airbag device in the period corresponding to the time t1 to the time t2), and the ultrasonic waves sufficiently appeared also in this crushable zone. Pay attention, time t
From 1 to time t2, the reference value for determining the speed calculation value ΔV is set to be higher than the conventional value (in the direction in which the air bag device becomes easier to operate) to ensure reliable operation of the air bag device. The inventors have made an invention relating to the present apparatus that can be obtained.

Explaining with the example of FIG. 3B, the vehicle safety device control apparatus according to the present invention sets the determination reference value of the speed calculation value ΔV to L1 only from time t1 to time t2, and otherwise. During the period (2), L2 (L1> L2) is set so that the airbag device can be reliably operated during the destruction of the so-called crushable zone.

FIG. 2 shows a flowchart showing a control procedure executed by the CPU 3 in order to realize the above-mentioned technical idea, which will be specifically described below with reference to the same figure. First, when a program stored in a storage unit (not shown) inside the CPU 3 is read and execution is started, it is determined whether or not the acceleration detected by the acceleration sensor 1 is a predetermined value A or more, that is, a collision. It is determined whether or not the level exceeds the level that is worthy of the determination (step 100 in FIG. 2).

When it is determined that the value is equal to or larger than the predetermined value A (YES), it is determined whether the ultrasonic sensor 2 detects the ultrasonic signal (step 1 in FIG. 2).
06) On the other hand, when it is determined that the acceleration detected by the acceleration sensor 1 is less than the predetermined value A (in the case of NO), it is determined whether or not the collision has ended (FIG. 2).
Step 102).

Whether or not the collision has ended is determined by, for example, the rate of change in acceleration, and when it is determined that the collision is ongoing (in the case of NO), it is determined whether or not the ultrasonic signal is generated in step 106. On the other hand, if it is determined that the collision has ended (NO) while proceeding to the determination process, various initial values and the like are reset (step 104 in FIG. 2), and the series of processes is terminated. A specific example of the value reset in step 104 is the integrated value of the speed calculation value ΔV.

In step 106, it is determined whether or not the ultrasonic sensor 2 has detected an ultrasonic wave generated due to a collision of a vehicle in which the present apparatus is mounted, and if it is determined that an ultrasonic wave has been detected (( If YES, the collision elapsed time determination process (step 108 in FIG. 2) is performed, while if it is determined that no ultrasonic wave is detected (NO), the energization of the squib 10 is started. The reference value of the speed calculation value ΔV, which is the determination reference, is set to L2 (step 112 in FIG. 2), and the process proceeds to the collision determination process (step 114 in FIG. 2).

On the other hand, in the collision elapsed time determination process (step 108 in FIG. 2), it is determined whether the elapsed time t from the start of the collision is within a predetermined range, that is, whether t1 <t ≦ t2 is satisfied. It is a thing. Here, the times t1 and t2 are values corresponding to the period during which the so-called crushable zone is destroyed as shown in the example of FIG. In the present embodiment, the times t1 and t2 are set in consideration of the result of simulation in which the structure of the vehicle and the like are added to the deployment time of the airbag required for this device from the viewpoint of driver safety and the like.

When it is determined that t1 <t≤t2 is satisfied (YES), the reference value of the speed calculation value ΔV is set to L1 (step 110 in FIG. 2), while
When it is determined that t1 <t ≦ t2 is not established (in the case of NO), the reference value is set to L2 (L1> L2) (step 112 in FIG. 2). Note that changing the reference value of the speed calculation value ΔV in this way means that the acceleration sensor 1
This is equivalent to practically changing the so-called sensor sensitivity of.

Therefore, instead of changing the reference value by so-called software as in the present embodiment, a detection circuit for processing the output signal of the acceleration sensor (in this embodiment, included in the acceleration sensor 1 shown in FIG. The same thing can be done even if the detection sensitivity is changed (for example, by adding a signal of a certain level to the output signal of the acceleration sensor so that a pseudo large deceleration is detected). Is.

After the reference value of the speed calculation value .DELTA.V is set as described above, a collision determination subroutine similar to the conventional one is executed (step 114 in FIG. 2). That is, although the details are omitted, if the processing contents of the subroutine are generally described, first, the speed calculation value ΔV is calculated by integrating the acceleration detected by the acceleration sensor 1. Next, it is determined whether or not the calculated speed calculation value ΔV exceeds the reference value (L1 or L2) set in the above process. When it is determined that the reference value is exceeded, the ignition signal is output from the CPU 3 MOS FET 12 constituting the ignition circuit 5
Will be applied to the gate of.

As a result, when the MOS FET 12 becomes conductive and the safing switch 14 is closed at this time, a current flows from the power supply circuit 7 to the heater wire 10a of the squib 10 and gas of an inflator (not shown) is supplied. The generating agent burns and a large amount of nitrogen gas is generated instantly,
The airbag will be deployed. Here, in the present embodiment, when the collision is such that the generation of ultrasonic waves is confirmed and the collision time is within a predetermined range (t1 <t ≦ t2), the airbag is deployed within this predetermined range. By increasing the reference value for determining the speed calculation value ΔV, which is the reference for determining whether or not to perform it, (making it a value closer to the positive electrode side), there is no time delay unlike in the past, and the air is accurately controlled. The back will be developed.

By the way, conventionally, in the example of FIG. 3A, the reference value of the speed calculation value ΔV is set so that the airbag is deployed near the time t1, and the speed calculation value ΔV is simply set. Depends on whether or not this exceeds one standard value,
The deployment of airbags was being decided.

However, in the frontal collision and the declination collision, the so-called bumper impact G is lower in the declination collision than in the frontal collision, that is, in FIG. 3 (a).
In the example, the acceleration tends to be low (the deceleration is large) as indicated by the dotted line in the area B. Therefore, the reference value of the speed calculation value ΔV is appropriate for any collision. It was difficult to set the air bag to be deployed properly. For example, if the reference value of the speed calculation value ΔV is set so that the airbag is appropriately deployed in the case of a declination collision, the airbag deployment will tend to be delayed in the case of a frontal collision. There was a tendency to end up.

On the other hand, the expansion of the airbag is performed while the so-called crushable zone before the destruction reaches the engine block is destroyed (in the example of FIG. 3, time t1).
To the time t2). Therefore,
In this embodiment, during the time t1 to the time t2 corresponding to the time when the crushable zone is destroyed,
Since the reference value of the speed calculation value ΔV is set to a reference value L1 (L1> L2) higher than the reference values at other times, the speed calculation value ΔV surely exceeds the reference value L1 within this time (see FIG. In the example of b), the airbag is deployed as described above without losing an appropriate operating time at the time ts).

In the case where the speed calculation value ΔV exceeds the reference value L2 during the initial stage from the time of collision occurrence, that is, until the time t1, (for example, in the case of declination collision), When the reference value L2 is exceeded, squib 1
The zero heater wire 10a is energized, and the airbag is deployed.

Also, for example, when traveling on a bad road such as a gravel road or when overcoming a curb on the road, deceleration occurs due to some impact on the vehicle body, but in some cases deceleration There is a possibility that the speed calculation value ΔV calculated from the above may exceed the judgment reference value. In such a case, the air bag operation is required in the conventional device that determines the operation of the air bag device only by determining whether or not the calculated speed value ΔV exceeds a certain value. There was a risk of a so-called malfunction, such that the device would operate although it was modest.

However, in the apparatus of this embodiment,
As described above, whether or not the ultrasonic wave is emitted is also a determining factor for determining the operation of the airbag device, and therefore, when traveling on a rough road or overcoming a curb as described above, the generation of the ultrasonic wave is the original. It's a short period of time compared to a collision,
For example, unlike the example of FIG. 3 (c), it is not considered to continue until time t1. Therefore, even if the speed calculation value ΔV exceeds the reference value, it is different from the conventional one. The above-mentioned malfunction does not occur.

In the above-described embodiment, the operation determining means is realized by the CPU 3 executing step 114 of FIG. In addition, claim 2
The sensitivity changing means in the described invention is such that the CPU 3 executes steps 110 and 112 of FIG.
The sensitivity changing means in the invention according to claim 3 is the CPU 3
Then, the steps 108, 110, and 112 of FIG. 2 are executed so that they are respectively realized. Further, the sensitivity changing means in the invention according to claims 4 to 6 is executed by the CPU 3 in steps 106 and 10 in FIG.
It is realized by executing steps 8, 110, and 112.

[0056]

As described above, according to the first and second aspects of the invention, the sensitivity of acceleration detection is substantially improved when the ultrasonic waves generated at the time of collision are detected. By configuring the above, unlike the conventional device that determines whether to operate the vehicle safety device, whether or not the vehicle speed obtained by integrating the detected acceleration exceeds a certain value. Even if the magnitude and change in acceleration at the time of a collision due to the difference in vehicle structure are different, it is possible to determine that it is the operation time of the vehicle safety device at an appropriate time. Highly versatile, capable of handling not only head-on collisions but also declination collisions, and more reliable than conventional systems that do not cause operational delays in vehicle safety devices such as airbag devices. A controller for vehicle safety devices is provided .

According to the third aspect of the present invention, the acceleration detection sensitivity is substantially changed according to the detection condition of the ultrasonic waves generated at the time of collision, so that, for example, a curb on a road can be detected. Since it is possible to increase the sensitivity of acceleration detection while avoiding the operation in the case where the operation of the vehicle safety device is not required as in the case of riding up, it is detected whether or not to operate the vehicle safety device. Unlike the conventional device that determines whether the vehicle speed obtained by integrating the acceleration exceeds a certain value, the magnitude and change of the acceleration during a collision due to the difference in vehicle structure are different. Even in this case, it is possible to obtain the judgment of the operation time of the vehicle safety device at an appropriate time. Therefore, it is highly versatile and can handle not only head-on collisions but also declination collisions, and is more reliable than the conventional one in which there is no delay in the operation of vehicle safety devices such as airbag devices. A controller for a high vehicle safety device is provided.

In particular, according to the invention of claim 4, when the ultrasonic wave is detected for a predetermined period, the sensitivity of acceleration detection is substantially increased in the predetermined period. In addition to the effect of the invention described in 3, it is possible to surely avoid a malfunction due to an unnecessary increase in sensitivity.

According to the fifth aspect of the present invention, when ultrasonic waves are detected during the destruction of the so-called crushable zone, the reference value of the motion determining means is changed during this time to improve the sensitivity of acceleration detection. Since it is set to be substantially high, in addition to the effect of the invention described in claim 3,
During the destruction of the crushable zone which requires the reliable operation of the vehicle safety device, it is possible to obtain the reliable operation of the vehicle safety device without causing an operation delay as compared with the conventional case.

Further, according to the invention of claim 6, the reference value for judging the vehicle speed is changed in such a direction that the operation of the vehicle safety device is started earlier, so that the effect of the invention of claim 3 described above. In addition, unlike the prior art, it is possible to obtain an earlier operation start of the vehicle safety device as compared with the related art.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a main part of a vehicle safety device control device according to the present invention.

FIG. 2 is a flowchart showing a procedure of operation control by a CPU.

3A and 3B are explanatory diagrams for explaining the operation principle of the present apparatus, in which FIG. 3A is a characteristic diagram showing a change in acceleration at the time of a collision, and FIG. FIG. 3C is a characteristic diagram showing a change in vehicle speed obtained from the above, and FIG. 6C is a characteristic diagram showing a change in ultrasonic waves generated in a collision.

FIG. 4 is an explanatory diagram for explaining a typical example of a collision.

FIG. 5 is a characteristic diagram showing a change over time in acceleration at the time of a collision.

[Explanation of symbols]

1 ... Acceleration sensor 5 ... Ignition circuit 2 ... Ultrasonic sensor 10 ... Squib 3 ... CPU 14 ... Safing switch

Claims (6)

[Claims] 1. An acceleration detecting means for detecting an acceleration at the time of collision of a vehicle, and an operation for determining whether or not a vehicle speed calculated by integrating the acceleration detected by the acceleration detecting means exceeds a reference value. A control device for a vehicle safety device, comprising: a determination means, wherein the operation of the vehicle safety device is controlled based on the determination result of the operation determination means, wherein an ultrasonic wave generated when a vehicle collides is detected. Vehicle safety device control, comprising: a sound wave detecting unit; and a sensitivity changing unit that substantially changes the detection sensitivity of the acceleration detecting unit when an ultrasonic wave is detected by the ultrasonic wave detecting unit. apparatus. 2. The control device for a vehicle safety device according to claim 1, wherein the sensitivity changing means changes the reference value in the operation judging means. 3. An acceleration detecting means for detecting acceleration at the time of collision of a vehicle, and an operation for judging whether or not a vehicle speed calculated by integrating the acceleration detected by the acceleration detecting means exceeds a reference value. A control device for a vehicle safety device, comprising: a determination means, wherein the operation of the vehicle safety device is controlled based on the determination result of the operation determination means, wherein an ultrasonic wave generated when a vehicle collides is detected. A vehicle safety device comprising: a sound wave detecting unit; and a sensitivity changing unit that substantially changes the detection sensitivity of the acceleration detecting unit for a certain period of time according to the detection result of the ultrasonic wave detecting unit. Control device. 4. The sensitivity changing means changes the reference value in the operation determining means over the predetermined period when the ultrasonic wave is detected by the ultrasonic wave detecting means for a predetermined period. A control device for a vehicle safety device as described. 5. The control device for a vehicle safety device according to claim 4, wherein the predetermined period corresponds to a period in which a front portion of the vehicle from the bumper portion to the engine block is destroyed in a frontal collision. 6. The control device for a vehicle safety device according to claim 4, wherein the sensitivity changing means changes the reference value in a direction in which it is easier to determine that the vehicle speed exceeds the reference value.