JP2000326822A - Vehicle occupant protection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an occupant protection device from being actuated by mistake due to a detection output of an acceleration sensor provided at the front of a vehicle, even if a slight impact is applied to the front of the vehicle, by combining detection outputs of both acceleration sensors, one provided at the front of the vehicle and the other provided at the center of the vehicle body. SOLUTION: In this system, the level of an acceleration detection signal of a center acceleration sensor 32 is very low even if a front acceleration sensor 31 generates an acceleration detection signal because of a local slight impact on the front of an automobile. Therefore the level of a filter signal generated by an LPF 33 is also very low and does not reach a reference level set by a reference level setting circuit 35. Thus, the comparison signal of a comparison signal 36 is at low level. As a result, an AND gate 37 does not output the acceleration detection signal of the front acceleration sensor 31 as a determination output signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle occupant protection system.

[0002]

2. Description of the Related Art Conventionally, for example, a vehicle occupant protection system includes a front acceleration sensor provided at the center of the front of the vehicle in the left-right direction and a center acceleration sensor provided at the center of the vehicle body in the front-rear and left-right directions. Some have been provided.

[0003] In this occupant protection system, the collision of the vehicle is determined by comparing the detected accelerations of the two acceleration sensors with the corresponding collision determination thresholds. When the collision is determined, the occupant protection device is activated. to start.

[0004]

However, in the above occupant protection system, for example, when a slight impact is locally applied to the front of the vehicle, the acceleration detected by the front acceleration sensor determines a corresponding collision determination threshold. If the value exceeds the threshold value, it is determined that the vehicle has collided, and the occupant protection device is erroneously activated.

On the other hand, the present inventor examined the detection status of the two acceleration sensors with respect to the slight impact on the automobile. According to this, when a slight impact is locally applied to the front portion of the vehicle due to the structure of the vehicle, the impact has a large effect on the front acceleration sensor, but has little effect on the center acceleration sensor. Do you get it.

By utilizing this, the detection output generated from the central acceleration sensor based on a slight impact to the front of the vehicle is used, and the occupant protection is performed by the detection output generated from the front acceleration sensor based on the slight impact. It has been found that erroneous activation of the device can be prevented.

In view of the above, the present invention focuses on the above points, and uses a combination of detection outputs of both acceleration sensors provided at the front part of the vehicle and the center part of the vehicle body to apply a slight impact to the front part of the vehicle. It is an object of the present invention to provide a vehicle occupant protection system that reliably prevents erroneous activation of an occupant protection device based on a detection output of an acceleration sensor provided at a front portion of a vehicle even if the vehicle occupancy increases.

[0008]

In order to solve the above-mentioned problems, a vehicle occupant protection system according to the first aspect of the present invention is provided at a front portion of a vehicle and operates based on a collision of the vehicle to increase acceleration. A mechanical acceleration detection switch (31) for detecting, an acceleration sensor (32) provided at the center of the vehicle body to detect the acceleration of the vehicle and generate an acceleration detection signal, and an acceleration detection signal from the acceleration sensor. Collision determining means (34,
43) and an occupant protection device (2) activated to protect an occupant based on at least one of detection of acceleration by a mechanical acceleration detection switch and determination of collision by collision determination means.
0, 10).

The occupant protection system is based on the detection of acceleration by a mechanical acceleration detection switch when the acceleration detection signal from the acceleration sensor is due to a local and slight impact on the front of the vehicle. Prohibition means (35, 36, 37, 38, 41, 4) for prohibiting the activation of
2).

According to this, even if the mechanical acceleration detection switch is actuated by a local and slight impact on the front part of the vehicle, the erroneous activation of the occupant protection device due to this can be reliably prevented by the activation prohibition means. . That is, by combining the acceleration sensor with the mechanical acceleration detection switch by the start prohibition unit, the acceleration sensor and the start prohibition unit play a role as a safing circuit for the mechanical acceleration detection switch. However, even if a local and slight impact is applied, the erroneous activation of the occupant protection device due to the detection output of the mechanical acceleration detection switch can be reliably prevented.

According to a second aspect of the present invention, there is provided a vehicle occupant protection system provided at a front portion of a vehicle for detecting an acceleration of the vehicle and generating an acceleration detection signal. A second acceleration sensor (32) provided at a central portion of the vehicle body to detect acceleration of the vehicle and generate an acceleration detection signal; and at least one of acceleration detection signals of the first and second acceleration sensors Collision determining means (34, 43) for determining the presence or absence of a vehicle collision based on the vehicle
And an occupant protection device (20, 10) that is activated based on the collision determination by the collision determination means and protects the occupant.

In the occupant protection system, when the acceleration detection signal of the second acceleration sensor is due to a local and slight impact on the front of the vehicle, a collision determination is performed based on the acceleration detection signal from the first acceleration sensor. It is characterized by including a start prohibiting means (vehicles 35, 36, 37, 38, 41, 42) for prohibiting the start of the occupant protection device based on the determination of the collision of the means.

According to this, even if a local and slight impact is applied to the front part of the vehicle, the erroneous activation of the occupant protection device due to the detection output of the first acceleration sensor can be reliably prevented by the activation prohibiting means. That is, by combining the second acceleration sensor with the first acceleration sensor with the start prohibition unit, the second acceleration sensor and the start prohibition unit function as a safing circuit with respect to the first acceleration sensor. Even if a local and slight impact is applied to the front part, erroneous activation of the occupant protection device due to the detection output of the first acceleration sensor can be reliably prevented.

According to a third aspect of the present invention, there is provided an occupant protection system for a vehicle, which is provided at a front portion of the vehicle and detects an acceleration of the vehicle and generates an acceleration detection signal. A second acceleration sensor (32) provided at the center of the vehicle body to detect the acceleration of the vehicle and generate an acceleration detection signal; and determining whether the vehicle has collided based on the acceleration detection signal of the first acceleration sensor. A first collision determination unit that determines the vehicle and a second collision determination unit that determines the presence or absence of a vehicle collision based on the acceleration detection signal of the second acceleration sensor.
4, 43) and an occupant protection device (20, 10) which is activated based on at least one of the first and second collision judgment means to judge the collision and protects the occupant.

In the occupant protection system, the occupant is determined based on the first collision judgment means judging a collision when the acceleration detection signal of the second acceleration sensor is due to a local and slight impact on the front of the vehicle. Activation prohibiting means for prohibiting activation of the protection device (35, 36, 37, 38, 41, 42)
It is characterized by having.

According to this, the same operation and effect as the second aspect can be achieved.

Note that the reference numerals in parentheses above indicate the correspondence with specific means described in the embodiments described later.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows an example in which the present invention is applied to an automobile airbag system.

The airbag system includes a driver's seat side airbag 10 and an activation device 20. The deployment of the airbag 10 causes a seated occupant of the driver's seat of the vehicle to be moved to the front of the vehicle. Protect from collision with obstacles. The activation device 20 activates the airbag 10
To expand.

The airbag system includes a collision judging device 30. The collision determination device 30 includes a front acceleration sensor 31 and a center acceleration sensor 32. The front acceleration sensor 31 is disposed at the center of the front of the vehicle in the left-right direction. The front acceleration sensor 31 is constituted by a normally-open mechanical acceleration detection switch, and the front acceleration sensor 31 turns on when the vehicle collides with an obstacle at the front of the vehicle to make the collision an acceleration. Detects and generates a high-level acceleration detection signal. Since the front acceleration sensor 31 is a normally-open mechanical acceleration detection switch as described above and generates an acceleration detection signal when it is turned on due to the collision, it can be said that the front acceleration sensor 31 also has a collision determination function of the vehicle.

On the other hand, the center side acceleration sensor 32 is disposed at the front, rear, left and right center portions of the body of the vehicle. The center-side acceleration sensor 32 is configured by an electronic acceleration sensor. When the vehicle collides with an obstacle at the front part thereof, the center-side acceleration sensor 32 detects this as an acceleration and outputs an acceleration detection signal. appear.

The airbag system includes a low-pass filter 33 (hereinafter, referred to as LPF 33) and a collision determination circuit 34. The LPF 33 receives an acceleration detection signal from the central acceleration sensor 32, A noise component is removed to generate a filter signal.

The collision judging circuit 34 compares the filter signal of the LPF 33 with a predetermined collision judging threshold, and judges that the vehicle is a collision only when the level of the filter signal is equal to or higher than the collision judging threshold. Generate a judgment output signal. Note that the collision determination threshold value in the collision determination circuit 34 is lower than the acceleration value required to turn on the front acceleration sensor 31 (that is, the collision determination threshold value).

The airbag system includes a reference level setting circuit 35, a comparison circuit 36, an AND gate 37, and an OR gate 38.

The reference level setting circuit 35 sets a reference level indicating a local slight impact applied to the front of the vehicle.

The comparison circuit 36 compares the filter signal of the LPF 33 with the reference level set by the reference level setting circuit 35, and generates a low-level comparison signal when the level of the filter signal is lower than the set reference level. When the level of the signal is equal to or higher than the set reference level, a high-level comparison signal is generated.

The AND gate 37 outputs the acceleration detection signal of the front acceleration sensor 31 as a collision determination signal when the comparison signal of the comparison circuit 36 is at a high level, and outputs this output when the comparison signal of the comparison circuit 36 is at a low level. Prohibit when.

The OR gate 38 outputs a collision judging signal of at least one of the AND gate 37 and the collision judging circuit 34 to the activating device 20 to activate it.

In the first embodiment configured as described above, when the vehicle collides with an obstacle such as a preceding vehicle at the front of the vehicle, both the front acceleration sensor 31 and the center acceleration sensor 32 generate an acceleration detection signal. I do.

Then, the LPF 33 removes noise from the acceleration detection signal of the central acceleration sensor 32 and outputs a filter signal to the collision determination circuit 34 and the comparison circuit 36.

The collision determination circuit 34 generates a collision determination signal when the level of the filter signal of the LPF 33 is equal to or higher than the predetermined threshold.

Since the level of the filter signal of the LPF 33 is higher than the reference level set by the reference level setting circuit 35, the comparison circuit 36 generates a comparison signal at a high level. Accordingly, the AND gate 37 generates an acceleration detection signal of the front acceleration sensor 31 as a collision determination signal.

As described above, the collision determination circuit 34 and A
When both of the ND gates 37 generate the collision determination signal, the OR
The gate 38 outputs these collision determination signals to the activation device 20 as activation signals.

For this reason, the activation device 20 is activated to deploy the airbag 10 and to appropriately protect the occupant in the driver's seat.

A case where a slight impact is locally applied to the front of the vehicle instead of the collision with the obstacle of the vehicle as described above will be described.

It is assumed that the front acceleration sensor 31 is turned on by such a small impact to generate an acceleration detection signal at a high level, and the center acceleration sensor 32 generates an acceleration detection signal.

However, since the level of the acceleration detection signal of the center side acceleration sensor 32 is slight as described above,
Very low. Therefore, the level of the filter signal generated by the LPF 33 is also very low and does not reach the reference level set by the reference level setting circuit 35. Therefore, the level of the comparison signal of the comparison circuit 36 is low.

As a result, the AND gate 37 inhibits the output of the acceleration detection signal of the front acceleration sensor 31 as the judgment output signal based on the low level comparison signal of the comparison circuit 36.

Therefore, the OR gate 38 is connected to the AND gate 3
7 does not generate a start signal, and as a result, the start device 20 does not start. The collision determination circuit 34 does not generate a collision determination signal because the level of the filter signal of the LPF 33 does not reach the predetermined collision determination threshold.

As described above, even if a slight impact is locally applied to the front portion of the vehicle and the front acceleration sensor 31 generates an acceleration detection signal at a high level, the acceleration detection signal The starting device 20 does not start by mistake. Therefore, the airbag 10 does not accidentally deploy due to the slight impact.

That is, the center side acceleration sensor 32 is connected to the LPF
33, reference level setting circuit 35, comparison circuit 36 and AN
By combining the front acceleration sensor 31 with the D gate 37, the center acceleration sensor 32, the LPF 33, the reference level setting circuit 35, the comparison circuit 36, and the AND gate 37 function as a safing circuit for the front acceleration sensor 31. Thus, even if a slight impact is locally applied to the front portion of the vehicle, it is possible to reliably prevent the activation device 20 from being erroneously activated by the detection output of the front acceleration sensor 31. (Second Embodiment) FIGS. 2 and 3 show a second embodiment of the present invention.

In the second embodiment, the microcomputer 39 includes the reference level setting circuit 35, the comparison circuit 36, and the AND gate 37 described in the first embodiment.
Has been adopted instead.

The microcomputer 39 is connected between the front acceleration sensor 31 and the LPF 33 and the OR gate 38.
The computer program is executed in accordance with the flowchart shown in FIG. 3 to perform the processing for judging the collision of the vehicle and the prohibition thereof based on the outputs of the front acceleration sensor 31 and the LPF 33. The computer program is stored in the ROM of the microcomputer 39 in advance. Other configurations are the same as those of the first embodiment.

In the second embodiment constructed as described above, the front acceleration sensor 31 detects the acceleration at a high level due to the collision with the obstacle at the front part of the vehicle, as described in the first embodiment. Generates a signal and LP
It is assumed that F33 generates a filter signal based on the acceleration signal of the center side acceleration sensor 32.

Then, the microcomputer 39 starts executing the computer program according to the flowchart of FIG. 3, and in step 40, the filter signal is input from the LPF 33. Then, in the next step 41, the level of the filter signal of the LPF 33 (hereinafter referred to as level G) is determined by comparing it with a predetermined reference level Gth. Here, the reference level Gth is equal to the set reference level of the reference level setting circuit 35 described in the first embodiment.

At this stage, the level G>
Because of the reference level Gth, the determination in step 41 is YE
It becomes S.

Next, in step 42, it is determined whether or not the level of the acceleration detection signal of the front acceleration sensor 31 is high. At this stage, as described above, since the level of the acceleration detection signal of the front acceleration sensor 31 is at the high level, the determination in step 42 is YES. Therefore, in step 43, a collision determination signal is output.

The collision determination circuit 34 generates a collision determination signal based on the filter signal of the LPF 33, as described in the first embodiment.

Accordingly, the OR gate 38 generates a start signal based on both the collision judgment signals of the microcomputer 39 and the collision judgment circuit 34 and outputs the start signal to the start device 20.

Thus, the activation device 20 deploys the airbag 10 by activation to protect the occupant.

As described in the first embodiment, when a slight impact is locally applied to the front of the vehicle instead of the collision with the obstacle of the vehicle, the front acceleration sensor 31 is activated. Assume that an acceleration detection signal is generated at a high level, and the center side acceleration sensor 32 generates an acceleration detection signal.

However, in substantially the same manner as described in the first embodiment, the level G of the filter signal of the LPF 33 is lower than the reference level Gth. Therefore, step 41
Is NO. Therefore, even if the front acceleration sensor 31 generates the acceleration detection signal at the high level as described above, the microcomputer 39 prohibits the transition from step 41 to step 42.

As a result, similarly to the first embodiment, even if a slight impact is locally applied to the front portion of the vehicle, the starting device 20 does not start erroneously.

In practicing the present invention, an electronic acceleration sensor and a collision determination circuit connected thereto may be employed instead of the front acceleration sensor 31. In this case, when the electronic acceleration sensor detects a collision of the vehicle and generates an acceleration detection signal, a collision determination circuit connected to the electronic acceleration sensor determines the level of the acceleration detection signal of the acceleration sensor by a predetermined collision determination. Threshold value (acceleration sensor 31
Only when it is greater than or equal to
The gate 37 generates a collision determination signal to be output.

With this, the same operation and effect as those of the above embodiments can be achieved. In this case, the collision determination circuit for the front acceleration sensor and the center acceleration sensor may be configured with a single collision determination circuit.

In implementing the present invention, the center side acceleration sensor 32 may be a mechanical acceleration detection switch.

In practicing the present invention, the front acceleration sensor 31 is not limited to a normally open type acceleration detection switch, but may be a mechanical type normally closed type acceleration detection switch. in this case,
Turning off the normally-closed acceleration detection switch corresponds to turning on the acceleration detection switch 31.

In practicing the present invention, the front acceleration sensor 31 may be provided at the front of the vehicle instead of at the center in the left-right direction.

In the above embodiments, the case where a slight impact is locally applied to the front portion of the vehicle has been described in the above embodiments. Instead, a slight impact may be applied to the center portion of the vehicle. Even when an impact is applied, the same operation and effect as those of the above embodiments can be achieved.

In practicing the present invention, the present invention may be applied to a vehicle airbag system without being limited to an automobile airbag system, and the present invention may be applied to a vehicle seat belt pretensioner. You may apply and implement.

[Brief description of the drawings]

FIG. 1 is an electronic circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the microcomputer of FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Airbag, 20 ... Activation device, 31 ... Front acceleration sensor, 32 ... Central acceleration sensor, 33 ... LPF, 3
4: collision determination circuit, 35: reference level setting circuit, 36:
Comparison circuit, 37 ... AND gate, 38 ... OR gate, 3
9 ... microcomputer.

Claims (3)

[Claims] 1. A mechanical acceleration detection switch (31) provided at a front portion of a vehicle and operating based on a collision of the vehicle to detect acceleration, and a mechanical acceleration detection switch provided at a central portion of a vehicle body of the vehicle. Sensor (32) for detecting acceleration and generating an acceleration detection signal
Collision determination means (34, 43) for determining the presence or absence of a vehicle collision based on an acceleration detection signal from the acceleration sensor; detection of acceleration by the mechanical acceleration detection switch and determination of a collision by the collision determination means An occupant protection device (20,
10) In the vehicle occupant protection system comprising: detecting an acceleration of the mechanical acceleration detection switch when the acceleration detection signal from the acceleration sensor is due to a local and slight impact to a front part of the vehicle. Activation prohibiting means (35, 36, 3) for prohibiting activation of the occupant protection device.
7, 38, 41, 42). 2. A first acceleration detection sensor (31) provided at a front portion of a vehicle to detect an acceleration of the vehicle and generate an acceleration detection signal, and an acceleration of the vehicle provided at a central portion of a vehicle body of the vehicle. The second acceleration sensor (3
2); collision determination means (34, 43) for determining the presence or absence of a vehicle collision based on at least one of the acceleration detection signals of the first and second acceleration sensors; and determination of a collision by the collision determination means. An occupant protection device (20, 10) for starting and protecting an occupant on the basis of a vehicle, wherein the acceleration detection signal of the second acceleration sensor is caused by a local, slight impact to the front of the vehicle. In this case, the start prohibiting unit (35, 36, 37, 38, 41, 41) prohibits the start of the occupant protection device based on the collision determination unit based on the acceleration detection signal from the first acceleration sensor.
42) An occupant protection system for a vehicle, comprising: 3. A first acceleration detection sensor (31) provided at a front portion of a vehicle and detecting acceleration of the vehicle to generate an acceleration detection signal, and an acceleration of the vehicle provided at a central portion of a vehicle body of the vehicle. The second acceleration sensor (3
2), first collision determination means for determining the presence or absence of a vehicle collision based on the acceleration detection signal of the first acceleration sensor, and determination of the presence or absence of a vehicle collision based on the acceleration detection signal of the second acceleration sensor 2 collision determining means (34, 43)
A vehicle occupant protection system comprising: an occupant protection device (20, 10) for starting and protecting an occupant based on a collision determination by at least one of the first and second collision determination means. When the acceleration detection signal of the acceleration sensor is due to a local and slight impact on the front part of the vehicle, a start prohibiting unit (for prohibiting the start of the occupant protection device based on the collision determination by the first collision determination unit) 35, 36, 37,
38, 41, 42). An occupant protection system for a vehicle, comprising: