JP7017453B2 - Vehicle frontal collision detector - Google Patents

Description

The present invention relates to a frontal collision detecting device that detects an acceleration generated in a vehicle by an acceleration sensor at the time of a frontal collision of the vehicle and controls the operation of an occupant restraining device such as an airbag according to the magnitude of the acceleration.

Normally, an occupant restraint device such as an airbag detects an impact applied to a vehicle as a deceleration by an acceleration sensor, obtains a calculated value based on the detected deceleration, and sets the calculated value as a preset threshold value and magnitude. The comparison is performed, and the operation of the airbag is controlled based on the comparison result.

Conventionally, as shown in FIG. 7, this type of frontal collision detection device includes a central acceleration sensor 3 provided in the electronic control unit (ECU) 2 of the airbag and a front acceleration sensor provided in the front part of the vehicle 1. The control unit 5 determines whether the airbag is deployed or not, based on the acceleration signal from the front acceleration sensor 4.

7 (a) to 7 (d) show the front irregular collision mode of the vehicle. The figure (a) shows a right offset collision, the figure (b) shows a left offset collision, the figure (c) shows a central pole collision, and the figure (d) shows a form of an underride collision in which a vehicle sneaks under a vehicle in front. Each is shown. Since the magnitude of the acceleration generated in the acceleration sensor of the ECU differs between the deployment requirement and the non-deployment requirement of the airbag, the acceleration from the central acceleration sensor 3 and the front acceleration sensor 4 is discriminated by the airbag deployment threshold, and the airbag is used. It controls the expansion / non-expansion of. In the figure, 6 and 7 indicate collision objects, respectively.

FIG. 8 is a detection logic diagram showing the airbag deployment system. The control unit 5 includes a main determination circuit 8 and a saving determination circuit 9. In the main determination circuit 8, the acceleration (G) in the front-rear direction (X) of the central front acceleration sensor 4 and the acceleration (G) in the front-rear direction (X) from the first acceleration sensor 3 in the ECU are input. Further, it is determined whether or not to deploy the airbag according to the magnitude of the acceleration. In the front acceleration sensor 3, when a collision occurs at a predetermined vehicle speed in the offset collision, the central pole collision, and the underride collision shown in FIGS. 7A to 7D, the generated acceleration (XG) in the front-rear direction exceeds the threshold value. When the acceleration (XG) from the first acceleration sensor 3 in the ECU 2 exceeds the lower threshold value (Lo), an occupant restraint device such as an airbag is deployed. Similarly, when the longitudinal acceleration (XG) from the first acceleration sensor 3 in the ECU 2 exceeds the upper threshold value (Hi), it is determined that the collision is full wrap and the airbag is deployed.

The safing determination circuit 9 is a circuit for taking measures against malfunction of the acceleration sensor 3. The second acceleration sensor 10 provided in the ECU 2 detects the acceleration (G) in the front-rear direction (X) and protects the deployment of the airbag due to malfunction of the front acceleration sensor 4, the first acceleration sensor 3, and the like. is doing.

In an irregular collision in which only the front part of the vehicle is deformed as shown in FIG. 7, since the generated acceleration in the front-rear direction of the ECU 2 is small, the front acceleration sensor is located near the collision position (front center position). 4 is installed, and it corresponds by detecting the deformation acceleration due to irregular collision. Some light vehicles and small vehicles have one front acceleration sensor 4 mounted on a radiator support upper member or the like in the engine room.

In Patent Document 1, when the offset collision cannot be discriminated by the magnitude of the acceleration generated in the acceleration sensor in the ECU, the deployment requirement of the airbag is discriminated by the magnitude of the angular velocity differential value by adding a yaw rate sensor. ing. Therefore, the front accelerometer can be removed by adding the yaw rate sensor.

Patent Document 2 discloses a technique for discriminating between a symmetric system collision (full wrap collision, central pole collision, underride collision) and an asymmetric system collision (offset collision) using a two-axis acceleration sensor in the ECU. This makes it possible to remove the front accelerometer.

Japanese Unexamined Patent Publication No. 2013-154838 Japanese Patent Application Laid-Open No. 2003-40077

By the way, in the system configuration of the front collision detection device shown in FIG. 7, an acceleration sensor is mounted on the upper part of the radiator support, and the rigidity is lower than when it is installed near either the left or right end of the radiator support. The accelerometer will be installed in. Therefore, it is necessary to protect the accelerometer and the wire harness for wiring the accelerometer to the ECU against an offset collision. In addition, since an acceleration sensor is mounted near the engine, it is necessary to take measures against heat damage, which increases the cost. In addition, there is a risk that Harnel disconnection may occur in the event of an offset collision.
Further, in the system configuration shown in Patent Documents 1 and 2, it is not possible to discriminate between an underride collision and a central pole collision, and there is a possibility that the airbag cannot be deployed at an appropriate time.

In view of the above, the present invention can secure the rigidity of the mounting portion of the accelerometer and eliminate the need for measures against heat damage, and further eliminate the need for countermeasures in terms of harness protection, and the central pole which cannot be detected by the acceleration sensor (2-axis type) of the ECU. It is an object of the present invention to provide a frontal collision detection device capable of discriminating collision types such as underride and underride.

In order to achieve the above object, in a preferred embodiment of the present invention, the front collision detection device detects an impact at the time of a collision by an acceleration sensor provided at the front of the vehicle, and the acceleration sensor is a vehicle. The two-axis acceleration detected by the acceleration sensor in the event of a frontal collision that is located near either the left or right end of the radiator support unit and is capable of detecting two axes in the front-rear direction and the left-right direction and does not hit the acceleration sensor directly. A control unit is provided that controls the operation of the occupant restraint device by making a collision determination according to the collision mode of the vehicle based on the signal.

The front accelerometer is placed near either the left or right end of the radiator support located at the front of the vehicle. As this front acceleration, one that can detect acceleration in two axes in the front-rear direction and the left-right direction is used. Since it is placed near either the left or right end of the radiator support part of the vehicle, as shown in FIG. 7, the front accelerometer is placed on either the left or right side of the radiator support part from the center position in the left-right direction of the radiator support upper member that was conventionally placed. It can be relocated near the edge. Therefore, the rigidity of the mounting portion of the acceleration sensor can be sufficiently ensured. Further, since the acceleration sensor can be rearranged on the side member of the radiator support portion, it is possible to eliminate the need for measures against heat damage from the engine, which has been conventionally required.

Furthermore, the front acceleration sensor is a sensor that can detect two axes in the front-back direction and the left-right direction, and from the combination of acceleration components generated in the front-back and left-right directions, a non-sensor that the collision object does not hit directly by the two-dimensional map of the discrimination circuit. It is possible to determine the collision form of the side offset collision and the central pole collision. Further, the offset collision and the underride collision on the accelerometer side that the colliding object directly hits can be discriminated only by the acceleration generated in the front-rear direction of the front accelerometer, as in the conventional technique shown in FIG.

According to the present invention, an acceleration sensor capable of detecting two axes in the front-rear direction and the left-right direction is arranged near either the left or right end of the radiator support portion of the vehicle, so that the rigidity of the mounting portion of the front acceleration sensor can be ensured. Measures against heat damage can be eliminated, and countermeasures are not required in terms of harness protection. Further, the 2-axis type front acceleration sensor has an effect that the collision form such as the central pole and the underride, which cannot be detected by the acceleration sensor (2-axis type) of the ECU, can be discriminated.

It is a control block diagram of the front collision detection device of the vehicle which is an embodiment of this invention. (A) is a system configuration diagram of the front collision detection device, and (b) is a perspective view of the radiator support unit showing the installation position of the front acceleration sensor. It is explanatory drawing which shows various irregular collision forms, (a) offset collision form on a non-sensor side, (b) offset collision form on a sensor side, (c) collision form to a central pole, (d) Indicates the underride collision form, respectively. It is an airbag deployment logic diagram of the control part of the front collision detection device. It is a figure which shows the magnitude of the generated acceleration in the front-rear direction (horizontal axis) / left-right direction (vertical axis) of the front acceleration sensor (when mounted on the left side) at each irregular collision. It is a table which shows the magnitude of the generated acceleration in the anteroposterior direction (X-axis direction) and the left-right direction (Y-axis direction) of an acceleration sensor in the deployment requirement / non-deployment requirement of an airbag in various collision forms. It is explanatory drawing which shows the relationship | The collision mode with the central pole and (d) indicate the underride collision mode. It is an airbag deployment logic diagram of the conventional frontal collision detection device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The vehicle 20 of the present embodiment is provided with a frontal collision detection device 24 that detects an impact at the time of a frontal collision by means of acceleration sensors 21, 22, and 23. Of the acceleration sensors, the acceleration sensor 21 provided on the front side is arranged near either the left or right end of the radiator support portion 12 at the front of the vehicle 20.

As shown in FIG. 2B, the radiator support portion 12 is arranged in the front portion of the engine room of the vehicle. The radiator support portion 12 is formed in a square frame shape from the upper member 13 on the upper side, the lower member 14 on the lower side, and the left and right side members 15 in the vertical direction connecting the upper member 13 and the lower member 14 on both the left and right sides. Has been done. A center reinforcing member 16 connecting the up member 13 and the lower member 14 is provided at the center position of the frame-shaped radiator support portion 12 in the left-right direction. The upper upper member 13 is hung on the front end portion of the apron upper member 17 forming the upper edges of the left and right side walls of the engine room. The left and right ends of the lower lower member 14 are coupled and supported by the front ends of the left and right front side members 18. The left and right side members 15 are coupled and held to the left and right front side members 18. Further, at an intermediate position between the left and right side members 15, a bumper reinforcement 19 that is coupled and held at the front ends of the left and right front side members 18 is installed. Then, in this example, the front acceleration sensor 21 is arranged near either the left or right end of the radiator support portion 12. As shown in FIG. 2B, the front acceleration sensor 21 of this example is arranged on the left side member 15, but is not limited to this, and the front acceleration sensor 21 is not limited to this, and either the left or right end of the upper member 13 of the radiator support portion 12 is used. It may be installed in the vicinity.

The front acceleration sensor 21 is capable of detecting acceleration in two axes, a front-rear direction (X-axis) and a left-right direction (Y-axis). The control unit 26, which controls the deployment / non-deployment of the occupant protection device 25 such as an airbag, determines the collision mode of the vehicle 20 from the two-axis acceleration signal detected by the front acceleration sensor 21, and corresponds to the collision mode. Whether or not to deploy an airbag or the like is determined based on the magnitude of acceleration.

The front acceleration sensor 21 has a function of detecting acceleration in two axes in the front-rear direction (X-axis) and the left-right direction (Y-axis). This 2-axis detection function allows the vehicle body to detect the front-back and left-right directions with one axis (for example, 45 degrees), even if it is a two-axis integrated acceleration sensor or a one-axis detection type side acceleration sensor. This can be achieved by adopting something that can be mounted on a frame or the like.

The front acceleration sensor 21 is connected to the electronic control unit (ECU) 27 of the airbag by a wire harness. A central acceleration sensor 22 and a safety sensor 23 for detecting acceleration in the front-rear direction (X-axis) are mounted in the ECU 27. The central acceleration sensor 22 is usually arranged in front of the floor tunnel in the vehicle interior. The central acceleration sensor 22 is preferably integrated with the electronic control unit (ECU) of the airbag, but the present invention is not limited to this, and the central acceleration sensor 22 may be provided separately.

As shown in FIG. 4, the front collision detection device 24 includes a main determination circuit 30 and a safety determination circuit 31. In the main determination circuit 30, the front acceleration sensor 21 is arranged near either the left or right end of the front part of the vehicle and can detect acceleration in two axes of the front-rear direction (X-axis) and the left-right direction (Y-axis). From the signal, the offset collision on the non-sensor side (see FIG. 3A) and the pole collision (see FIG. 3C) in which the colliding object does not hit directly can be discriminated by the two-dimensional map 32. The sensor-side offset collision (see FIG. 3B) and the underride collision (see FIG. 3D) in which the colliding object directly hits occur in the front-rear direction (X-axis direction) of the front accelerometer 21 as in the conventional case. It has a discrimination circuit 33 for determining whether or not the acceleration to be performed exceeds a threshold value. In FIG. 4, "Fr" means the front, "XG" means the acceleration in the front-rear direction, and "YG" means the acceleration in the left-right direction. Since the other determination circuits are the same as the determination circuit shown in FIG. 8, the description thereof will be omitted.

FIG. 5 is a graph showing the magnitude of the generated acceleration in the front-rear direction (X-axis direction) / left-right direction (Y-axis direction) of the front acceleration sensor 21 (when mounted on the left side) at the time of each irregular collision. The vertical axis is the acceleration in the left-right direction (Y-axis direction) of the front acceleration sensor 21, and the horizontal axis is the acceleration in the front-rear direction (X-axis direction) of the front acceleration sensor 21.

In FIG. 5, in the case of a right offset (high speed) collision, the acceleration is large because the vehicle decelerates (acceleration is small) in the front-back direction (X-axis direction) and the deformation is large in the left-right direction (Y-axis direction). The same is true for pole (high speed) collisions. In such a case, the control unit 26 determines that the requirement for deploying the airbag is satisfied, and deploys and operates the airbag.

In FIG. 5, in the case of a right offset (low speed) collision and a pole (low speed) collision, the acceleration in the front-rear direction is minimal and the deformation in the left-right direction is medium, so the airbag is not deployed. .. In the case of a full wrap (low speed) collision, the airbag is not deployed because it is medium in the front-rear direction and small in the left-right direction. In the case of an underride (low speed) collision and a left offset (low speed) collision, the acceleration in the front-rear direction (X-axis direction) is medium, and the acceleration in the left-right direction (Y-axis direction) is large. That is, in the case of an underride collision or a left offset collision, since the seat surface of the sensor is directly hit, the acceleration generated from the front to the rear is relatively large due to deceleration and deformation in the front-rear direction (X-axis direction), and the left-right direction (Y-axis direction). Direction) tends to increase in the acceleration generated by the vibration (both left and right directions).

FIG. 6 shows the collision mode and the magnitude of acceleration in FIG. In the table, full wrap (high speed), left offset (high speed), and underride (high speed) have a large acceleration of occurrence of airbag (A / B) deployment requirements, and can be separated from airbag (A / B) non-deployment requirements. can. In addition, the thick frame portion can separate the deployment requirement and the non-deployment requirement by the two-dimensional map 32 which is a combination of the acceleration in the front-rear direction (X-axis direction) and the acceleration in the left-right direction (Y-axis direction) of the airbag deployment requirement. ..

As described above, in the present embodiment, the front accelerometer, which is arranged near either the left or right end of the radiator support portion of the vehicle and can detect the two axes of the front-rear direction and the left-right direction, is located at the center position in the left-right direction of the vehicle. Relocation from near the end (near the end of the radiator support upper member or side member) from the center position of the radiator support upper member, etc. The offset collision on the sensor side and the central pole collision are discriminated, and the offset collision and underride collision on the accelerometer side that the colliding object hits directly are discriminated only by the acceleration generated in the front-rear direction of the accelerometer as before. There is.

Therefore, not only can the rigidity of the mounting portion of the accelerometer be ensured and measures against heat damage can be eliminated, but also measures against harness protection are not required. Further, it is possible to discriminate a collision mode such as an underride and a central pole that cannot be detected by the acceleration sensor (2-axis type) of the ECU.

When the front acceleration sensor is arranged in the bumper reinforcement 19 as shown in FIG. 2B, the underride collision cannot be detected, and when the front acceleration sensor is arranged in the front side member 18, the underride collision cannot be detected. Neither a central pole collision nor an underride collision can be detected. On the other hand, when the front acceleration sensor 21 is arranged near either the left or right end of the radiator support portion 12 of the vehicle as in the present embodiment, the front acceleration sensor 21 does not hit directly, an offset collision, a central pole collision, and the like. Furthermore, it is possible to determine the underride collision and determine whether the airbag is deployed or not.

Further, the present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made within the scope of the present invention. For example, in the present embodiment, an example in which the front acceleration sensor is arranged near the left end of the radiator support portion is shown, but it is needless to say that the front acceleration sensor may be arranged near the right end of the radiator support portion of the vehicle.

1 Vehicle 2 Electronic control unit (ECU)
3 Central acceleration sensor 4 Front acceleration sensor 5 Control unit 6, 7 Collision target 12 Radiator support unit 13 Upper member 14 Lower member 15 Side member 16 Center reinforcement member 17 Apron upper member 18 Front side member 19 Bumper reinforcement 20 Vehicle 21 Front acceleration sensor 22 Central acceleration sensor 23 Safety sensor 24 Front collision detection device 25 Passenger protection device for airbags, etc. 26 Control unit 27 Electronic control unit (ECU) for airbags
30 Main judgment circuit 31 Safety judgment circuit 32 Two-dimensional map judgment circuit 33 Front-back acceleration judgment circuit

Claims (1)

It is a frontal collision detection device that detects the impact at the time of a collision by an acceleration sensor installed at the front of the vehicle.
The accelerometer is arranged near either the left or right end of the radiator support portion of the vehicle, and can detect two axes in the front-rear direction and the left-right direction.
In the event of a frontal collision that does not hit the acceleration sensor directly, a control unit is provided that determines the collision according to the collision mode of the vehicle based on the two-axis acceleration signal detected by the acceleration sensor and controls the operation of the occupant restraint device. A frontal collision detector characterized by this.

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