JPH08127306A - Air bag control device - Google Patents

Abstract

PURPOSE: To avoid an air bag device operating in the event or a low speed collision and to cause the device to operate only in the event of a medium collision, by enlarging a threshold in case a first change value of speed does not reach a certain value within a predetermined time span after the first change value of speed becomes positive. CONSTITUTION: An inflator is actuated if a first change value of speed V1 and a second change value of speed V2 have reached respectively thresholds TH1, TH2. If the first change value of speed V1 does not reach the threshold TH1 though a computed lapse of time has reached a threshold t1, a threshold for actuation determination is increased (steps 146 to 152). Actuation being avoided in case of a low speed collision, an air bag device is enabled to be actuated for a medium speed (steps 146 to 152). The threshold for the second change value of speed V2 is increased when a ratio of the first change value of speed V1 to the second change value of speed V2 is equal to or greater than a threshold K or when a ratio of the second change value of speed V2 to the first change value of speed V1 is smaller than the predetermined threshold K (steps 152 to 160).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag control device for protecting an occupant from a collision so that the airbag control device can be operated at good timing. In particular, the present invention relates to a device that avoids the operation of an airbag device during a low speed collision and operates only during a medium speed collision.

[0002]

2. Description of the Related Art Conventionally, the operation timing of an air bag system is set when a speed change value obtained by integrating a deviation of a deceleration of a vehicle at the time of a collision with respect to a predetermined threshold value is a predetermined value or more. However, even at a low speed (about 15 km / h), the speed change value may exceed the predetermined value, so it is necessary to avoid the operation of the airbag device in a low speed collision that does not require the operation of the airbag. there were. As a solution to this, as disclosed in Japanese Patent Application Laid-Open No. 4-133840, a method of avoiding the operation at low speed by increasing the threshold value of the integral calculation of the vehicle deceleration, or Japanese Patent Application Laid-Open No. 3-2
As disclosed in Japanese Patent No. 53441, there is known a method of avoiding the operation of an airbag device at a low speed by increasing a predetermined speed change value after a lapse of a certain time after the start of calculation.

[0003]

However, by increasing the threshold value of the integral calculation of the vehicle deceleration, the medium speed (3
(0 km / h or so) In addition to the problem that the collision determination time at the time of collision becomes long, the fluctuation of the integration start time becomes large by increasing the predetermined value of the speed change value after a certain time has elapsed after the start of the calculation. There was a problem of becoming. Therefore, the design of the bag and the inflator absorbs these fluctuations, so that it takes time for trial manufacture and adjustment.

Therefore, an object of the present invention is to avoid the operation of the airbag device in a low-speed collision of the vehicle and to stabilize the operation timing in a medium-speed collision, so that it takes no time for designing, prototyping, and adjusting. An airbag device and an airbag device suitable for the weight of the vehicle.

[0005]

In order to solve the above problems, the structure of the present invention detects a deceleration of a vehicle by an acceleration sensor and integrates the deceleration and a predetermined speed change value set in advance. In the airbag control device that compares the threshold value and starts the inflator that ejects gas when the speed change value reaches a predetermined threshold value and inflates the airbag with the gas from the inflator, the first standard of deceleration. A first speed change value calculating means for calculating a first speed change value which is a time integration of a deviation with respect to a value, and a second speed change value which is a time integration of a deviation with respect to a second reference value larger than the first reference value A second speed change value calculating means and a starting means for starting the inflator when the second speed change value reaches a threshold value, and the time after the first speed change value becomes positive is a predetermined time. To When one velocity change value does not reach the predetermined value, characterized by increasing the threshold.

In the second aspect of the invention, the deceleration of the vehicle is detected by the acceleration sensor, the speed change value obtained by integrating the deceleration is compared with a predetermined threshold value, and the speed change value is In an airbag control device that activates an inflator that ejects gas when a predetermined threshold is reached and inflates an airbag with the gas from the inflator, the first integral is a time integral of a deviation of a deceleration from a first reference value. A first speed change value calculating means for calculating a speed change value,
Second speed change value calculating means for calculating a second speed change value, which is a time integration of a deviation with respect to a second reference value larger than the first reference value, and an inflator when the second speed change value reaches a threshold value. It is characterized in that it comprises start-up means for starting and ratio calculating means for calculating the ratio of the second speed change value to the first speed change value, and increases the threshold value when the ratio is below a predetermined value.

[0007]

The first effect is that the time after the positive value of the first speed change value, which is the time integration of the deviation of the vehicle deceleration from the first reference value, becomes positive at a predetermined time. When the value is equal to or less than the predetermined value, the predetermined threshold value of the second speed change value for activating the inflator of the airbag device is increased. (Claim 1) The second action is, when the ratio of the second speed change value to the first speed change value is equal to or less than a predetermined value, a predetermined second speed change value for activating the inflator of the airbag device. Increase the threshold of. (Claim 2)

[0008]

The first effect is that in a large vehicle, the impact force is absorbed at the front portion of the vehicle during a low-speed collision, so the deceleration that occurs at the beginning of the collision is small. During a medium-speed collision, the deceleration at the initial stage of the collision is larger than that during a low-speed collision.Therefore, when the first speed change value is small for a predetermined time after the first speed change value becomes positive, By increasing the predetermined threshold value of the second speed change value for activating the inflator of the back device, the operation of the airbag device at a low speed collision is avoided, and the operation of the airbag device is performed only at a medium speed collision. Can be done. (Claim 1) A second effect is that, in a small-sized vehicle, the impact force is not so much absorbed in the front portion of the vehicle during a medium-speed collision,
The deceleration that occurs at the beginning of a collision is larger than that of a large vehicle, that is, when the ratio of the second speed change value to the first speed change value is less than or equal to a predetermined value, the first deceleration for starting the inflator of the airbag device is started. By increasing the predetermined threshold value of the two-speed change value, it is possible to avoid the operation of the airbag device at the time of a low speed collision, and to operate the airbag device only at the time of a medium speed collision. (Claim 2)

[0009]

EXAMPLES The present invention will be described below based on specific examples. FIG. 1 is a schematic diagram showing the configuration of this embodiment. The airbag control device 9 inputs the acceleration signal detected by the acceleration sensor 15 and executes a collision determination calculation. When a collision is determined, a signal for activating the inflator is sent to the ignition device 4 of the inflator, respectively. It outputs to the transistor 31 connected in series. When this transistor is turned on, the ignition device 4 is energized and the inflator is activated.

Next, details of the control device 9 are shown in FIG. The control device 9 includes a CPU 91, a ROM 92 storing a control program and a collision determination program, an externally writable EEPROM 93, and a RAM 9 storing various data.
4 and A / D converter 95 and IF (interface) 9
6 and 6. RAM94 has an acceleration sensor 1
A threshold value memory area 941 for storing a threshold value for determining activation of the inflator corresponding to the physical displacement amount of the vehicle based on the deceleration signal from 5 is formed. The deceleration signal from the acceleration sensor 15 is input to the CPU 91 via the IF 96 and the A / D converter 95.

3 to 5 are main flowcharts showing the processing procedure of the CPU 91 in the control device 9. First, at step 100 in FIG. 3, 1 (ms) is set for the elapsed time t of calculation.
Step 1
At 02, the deceleration G of the vehicle is read from the acceleration sensor 15. Here, the direction of acceleration applied to the vehicle is negative and the direction of deceleration G is positive.

Next, at step 104, the vehicle deceleration G is set to -2 in order to prevent the airbag from operating in the event of a rear collision of the occupant.
(G) It is determined whether it is smaller than. Here, g means the unit of acceleration and deceleration G, and 1 (g) is 9.8 m /
s ² . In FIG. 3, the vehicle deceleration G is -2 (g).
If it is smaller, YES is determined in step 104, 2 is added to the 2g counter in step 106,
Subsequently, in step 108, it is determined whether or not the 2g counter is 15 or more.

When the 2g counter is 15 or more,
It is determined to be YES in step 108, then the 2g flag is set to 1 in step 110, and 2g in step 118
When it is determined whether or not the flag is 1, it is determined to be YES, and in the following step 120, the first speed change value V1, the second speed change value V2, and the operation elapsed time t are all set to zero, and the process returns in step 122. . When the 2g counter is smaller than 15, it is determined to be NO in step 108,
In step 118, it is determined as NO in the determination of the 2g flag, and the process proceeds to the integral calculation of step 124.

In step 104, the vehicle deceleration G is -2.
In the case of (g) or more, it is determined as NO and the following step 1
At 12, the 1 is subtracted from the 2g counter. If the value of the 2g counter is greater than or equal to zero, N is returned in step 114.
When it is determined to be O, the process proceeds to step 118. When the value of the 2g counter is smaller than zero, YES is determined in step 114, the 2g counter is set to zero in step 116, and the 2g flag is set to zero, and the process proceeds to step 118.

In the processing from step 104 to step 118 shown above, when the 2g counter reaches 15 or more, the first speed change value V1, the second speed change value V2, and the calculation elapsed time t are all cleared. , -2 (g) and the deceleration smaller than -2 (g) continues for 7.5 ms or more, it is considered that the vehicle is not in a collision and the inflator is not started.

Subsequently, when it is determined in step 118 that the 2g flag is not 1, the routine proceeds to step 124, where the integral calculation of the deceleration G is performed. First speed change value V1
Is the integral of the deviation of the vehicle deceleration G from the threshold value 1 (g), and the second speed change value V2 is the threshold value α of the vehicle deceleration G.
It is the integral of the deviation from (g). Where the threshold α
(G) is larger than 1 (g), and in this embodiment, the threshold value α
(G) was set to 6 (g). After the integral calculation in step 124, when the first speed change value V1 is negative, step 1
When NO is determined in step 26, the process proceeds to step 120, and the first speed change value V1, the second speed change value V2, and the calculation elapsed time t are all cleared.

First speed change value V1 and second speed change value V2
When both are equal to or greater than zero, the process proceeds to step 130 in FIG. 4, and the magnitude of the elapsed arithmetic time t is compared with the threshold value t1. This threshold value t1 indicates that the impact of a hammer blow or the like is caused by the ECU.
A large deceleration G occurs when it is added near
This prevents the air bag device from operating, and is provided for distinguishing a low-speed collision and a medium-speed collision described later. FIG. 6 shows a waveform of the deceleration G at the time of hammer blow. The calculation time is long because the pulse width is short and the waveform is a vibration waveform. Ignition is prohibited for several ms.

In step 130 of FIG. 4, when the calculation elapsed time t, that is, the time from the start of the integral calculation is larger than the threshold value t1, it is determined as NO, and the routine proceeds to step 146. In step 130, the calculated elapsed time t is the threshold value t1.
In the following cases, YES is determined and the process proceeds to step 132. In step 132, it is determined to be YES when t = t1, the process proceeds to step 134, and when the first speed change value V1 is smaller than the threshold value TH1 in step 134, it is NO.
Then, the process proceeds to step 146.

At step 134, the first speed change value V1
Is greater than or equal to the threshold value TH1, YES is determined, and the high-speed collision flag is set to 1 in step 136. In step 132, when t ≠ t1, that is, when t <t1, it is determined to be NO, the process proceeds to step 138, and the operation determination is not performed. In this embodiment, the threshold value t1
Was set to 6 ms.

With respect to the processing contents of steps 130 to 136 shown above, when the time from the start of the integral calculation does not reach 6 ms, the airbag device is not judged to operate, and the integral calculation is started. When the time reaches 6 ms, the operation is judged, and even if the deceleration G is generated by the hammer blow, the operation is not operated for 6 ms.

In step 132, when the calculated elapsed time t is smaller than the threshold value t1, the process proceeds to step 138, and the threshold value of the calculated elapsed time t is determined. That is, when the calculated elapsed time t is larger than the threshold value (xx + 1), step 1
When NO is determined in 38, the process returns in step 144. When the calculated elapsed time t is equal to or less than the threshold value (xx + 1), YES is determined in step 138, and the threshold value determination of the second speed change value V2 is performed in step 140.

When the second speed change value V2 is smaller than the threshold value TH2, NO is determined in step 140, and the process returns in step 144. When the second speed change value V2 is greater than or equal to the threshold value TH2, YES is determined in step 140, and subsequently, the first speed change value V is determined in step 142.
The first and second speed change values V2 are set to zero, and the process returns at step 144.

Steps 138 through 144 above
The processing contents up to are reset even if the second speed change value V2 reaches the threshold value TH2 when the calculation elapsed time t is less than 6 ms and the calculation elapsed time t is equal to or less than the threshold value (xx + 1). Is to do. As a case where the deceleration of full scale (-36 g) or more occurs in a short time, disconnection of the acceleration sensor 15 is considered.

Therefore, the calculated elapsed time t is the threshold value (xx +
1) In the following, when the second speed change value V2 reaches the threshold value TH2, it is considered that the deceleration G other than the collision of the vehicle has occurred due to the disconnection of the acceleration sensor 15, and the operation determination is not performed. . It should be noted that xx in step 138 means ignition time and is defined by the equation 1.

[0025]

Xx = TH2 / G (1) where TH2 is the threshold value of the second speed change value V2 and G is the vehicle deceleration at full scale.

At step 134, the first speed change value V1
Is greater than or equal to the threshold TH1, the high-speed collision flag is set to 1, the process proceeds to step 146, and YE is performed in step 146.
It is determined to be S, and the process proceeds to step 148. Step 1
When the second speed change value V2 is equal to or greater than the threshold value TH2 at 48, YES is determined, and at step 150, the inflator is ignited.

NO in steps 130 and 134
If it is determined that the high-speed collision flag is zero, it is determined to be NO in step 146, and the process proceeds to step 152. In step 152, when the ratio between the first speed change value V1 and the second speed change value V2 is greater than or equal to a predetermined threshold value K, YE
It is determined to be S, and the irregular collision flag is set to 1 in step 154.

In the following step 156, the irregular collision flag is 1, so that it is determined to be YES and the routine proceeds to step 158, where the second speed change value V2 and the threshold value TH3 are compared. Here, the threshold TH3 is larger than the threshold TH2.
When the second speed change value V2 is equal to or greater than the threshold value TH3, YES is determined in step 158, and ignition is performed in subsequent step 160.

First speed change value V1 and second speed change value V2
When the ratio of the
Since it is determined to be O and the irregular collision flag is zero, it is determined to be NO in the following step 156, and the process proceeds to step 162 of FIG. Further, the second speed change value V2 is the threshold value T
When it is smaller than H3, NO is determined in Step 158, and the routine proceeds to Step 162.

In the processes of steps 130 to 136 and 146 to 150 described above, the first speed change value V1 and the second speed change value V2 are the threshold values TH1 and TH2, respectively, when the elapsed time t of calculation is 6 ms. If it reaches, the inflator is started. In addition, the line from step 146 to step 152 is as follows when the first speed change value V1 does not reach the threshold value TH1 even if the operation elapsed time t reaches the predetermined threshold value t1.
It means increasing the threshold value of the operation determination.

Here, the waveforms of the deceleration G in the case of low speed (about 15 km / h) collision and in the case of medium speed (about 30 km / h) collision are shown in FIG. 7 and FIG. Indicates that the deceleration G rises more gently at the initial stage of the collision than in the medium-speed collision, so that the first speed change value V1 does not reach the threshold TH1 even after the elapse of the predetermined time threshold t1.
By providing the line from step 146 to step 152, the operation in the low speed collision is avoided, and the operation of the airbag device in the medium speed collision is enabled.

The processing of steps 152 to 160 is performed when the elapsed time t of calculation is 6 ms or more.
When the ratio between the first speed change value V1 and the second speed change value V2 is greater than or equal to the threshold value K, the threshold value of the second speed change value V2 is set to TH2.
In other words, the calculated elapsed time t is 6 ms or more, and the ratio of the second speed change value V2 to the first speed change value V1 is a predetermined threshold value K1.
When it is smaller, the threshold value of the second speed change value V2 is increased.

Here, as shown in FIG. 7, in the deceleration G waveform in a low-velocity collision, the deceleration G rises gently, so the proportion of the deceleration component is lower than that of the high deceleration component. When the ratio of the second speed change value V2 to the first speed change value V1 is smaller than the predetermined threshold value K for a predetermined time or more, the low speed collision is increased by increasing the threshold value of the second speed change value V2. Can be avoided.

When NO is determined in steps 148, 156 and 158 of FIG. 4, 1 is subtracted from the threshold value TH4 in step 162 of FIG. 5, and the first speed change value V1 and the threshold value TH4 are determined in step 164. Make a comparison of. When the first speed change value V1 is equal to or greater than the threshold value TH4, YES is determined in step 164 and the process proceeds to step 166. If the calculated elapsed time t is 120 ms or less in step 166, YES is determined, and step 168 is performed. Is ignited at.

In step 166, the calculated elapsed time t is 12
When it is larger than 0 ms, it is determined as NO and step 170
Then, in step 170, the first speed change value V1, the second speed change value V2, and the calculation elapsed time t are all cleared,
The process returns at step 172. When the first speed change value V1 is smaller than the threshold value TH4 in step 164, N
It is determined to be O, and the process returns at the following step 172.

The process from step 162 to step 172 is to reset the first speed change value V1 even when the first speed change value V1 reaches the threshold value TH4 when the elapsed time t is 120 ms or more. The purpose of this is to prevent operation when a voltage shift occurs.
That is, if an offset displacement occurs in the acceleration sensor 15, for example, if an offset voltage displacement occurs in the negative direction by 1 g, it cannot be distinguished from a deceleration input of 1 g. It may lead to judgment.

In order to avoid the operation of the acceleration sensor 15 due to the offset voltage shift, if the first speed change value V1 does not reach the threshold value TH4 even if the calculation is performed for a certain time or longer, it is determined that the collision does not occur, and the determination calculation is performed. Will be reset. In this embodiment, the threshold value TH4 is set to decrease by 1 with the elapsed time t of calculation. In addition, in the present embodiment, 10 at the time of irregular collision at 30 km / h.
In order to achieve 0% ignition, the calculation elapsed time t in that case is 1
Since it has reached 00 ms, the threshold is temporarily set to 120
ms.

According to the present embodiment, due to the above operation, the time after the first speed change value V1 becomes positive, that is, the calculation elapsed time t.
Is increased to a predetermined threshold value t1 by increasing the threshold value for operation determination according to the magnitude of the first speed change value V1, thereby avoiding the operation of the airbag device during a low speed collision, and It is possible to operate at the time of collision.
When the ratio between the first speed change value V1 and the second speed change value V2 is larger than the predetermined threshold value K, the second speed change value V2
By increasing the threshold value of 1, it is possible to more easily determine the operation in a medium-speed collision, and it is also possible to easily prevent the operation when dropping into a groove or the like.

Further, it is possible to sufficiently deal with the difference in the waveform of the deceleration G at the time of a collision between a large vehicle and a small vehicle. That is, in a large-sized vehicle, the deceleration G at the time of a medium-speed collision is gentle, and the waveform is similar to that at the time of a low-speed collision. Therefore, when the operation elapsed time t becomes equal to or greater than the threshold t1, the operation determination It is possible to prevent the operation at the time of low speed collision by increasing the threshold value of. Further, in a small-sized vehicle, the deceleration G rises quickly in the initial stage of a medium-speed collision, so the ratio of the second speed change value V2 to the first speed change value V1 is small, and the ratio is a predetermined value within a predetermined time. By increasing the threshold value of the second speed change value V2 when it is the following, it is possible to prevent the operation of the airbag device at the time of a low speed collision. Therefore, it is possible to easily change the threshold value between a large vehicle and a small vehicle. Can be done by.

[Brief description of drawings]

FIG. 1 is a structural diagram showing a configuration of a first embodiment according to the present invention.

FIG. 2 is a detailed block diagram of a control device.

FIG. 3 is a main flowchart showing a processing procedure of a CPU of a control device.

FIG. 4 is a main flowchart showing a processing procedure of a CPU of the control device.

FIG. 5 is a main flowchart showing a processing procedure of a CPU of the control device.

FIG. 6 is a waveform diagram of deceleration during hammer blow.

FIG. 7 is a waveform diagram of deceleration at a low speed (about 15 km / h) collision.

FIG. 8 is a waveform diagram of deceleration at a medium speed (about 30 km / h) collision.

[Explanation of symbols]

 4 Ignition device 9 Airbag control device 15 Acceleration sensor 31 Transistor G Vehicle deceleration V1 First speed change value V2 Second speed change value t Calculation elapsed time xx Ignition time TH1, TH4 First speed change value threshold TH2, TH3 (2) Threshold value of speed change value t1 Threshold value of operation elapsed time K Threshold value of ratio between first speed change value and second speed change value

Claims (2)

[Claims] 1. A deceleration of a vehicle is detected by an acceleration sensor, a speed change value obtained by integrating the deceleration is compared with a predetermined threshold value set in advance, and the speed change value reaches the predetermined threshold value. At the time, in an airbag control device that activates an inflator that ejects gas and inflates the airbag with the gas from the inflator, calculates a first velocity change value that is a time integral of a deviation of the deceleration from the first reference value. First speed change value calculating means, second speed change value calculating means for calculating a second speed change value which is a time integration of a deviation with respect to a second reference value larger than the first reference value, and the second speed And a starting means for activating the inflator when the change value reaches the threshold value, wherein the first speed change value is constant at a predetermined time after the first speed change value becomes positive. An airbag control device, wherein the threshold value is increased when the value is not reached. 2. A deceleration of a vehicle is detected by an acceleration sensor, a speed change value obtained by integrating the deceleration is compared with a predetermined threshold value set in advance, and the speed change value reaches the predetermined threshold value. At the time, in an airbag control device that activates an inflator that ejects gas and inflates the airbag with the gas from the inflator, calculates a first velocity change value that is a time integral of a deviation of the deceleration from the first reference value. First speed change value calculating means, second speed change value calculating means for calculating a second speed change value which is a time integration of a deviation with respect to a second reference value larger than the first reference value, and the second speed When the change value reaches the threshold value, a starting means for starting the inflator, and a ratio calculation means for calculating a ratio of the second speed change value to the first speed change value, Airbag control device characterized by serial ratio to increase the threshold when it is less than a predetermined value.