JP2019051813A - Front collision detection device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frontal collision detection device for discriminating a collision form of a frontal collision using a side acceleration sensor and reducing the cost. SOLUTION: Side acceleration sensors 7 and 8 are provided near both ends in the vehicle width direction of the vehicle body behind the front end of the vehicle interior, and a main acceleration sensor 6 is arranged between them, from each acceleration sensor 6, 7 and 8. Based on the difference between the detected acceleration signals, the frontal collision mode of the vehicle, for example, full-wrap collision, offset collision, and center collision is discriminated, and the operating conditions of the occupant restraint device 14 are changed according to the frontal collision mode, and a small detection value is obtained. However, it will be possible to operate according to the collision form. [Selection diagram] FIG. 5

Description

  The present invention relates to a front collision detection device that detects an acceleration generated in a vehicle at the time of a frontal collision of a vehicle by an acceleration sensor, and controls the operation of an occupant restraint device such as an air bag based on the magnitude of the acceleration.

  Usually, an occupant restraint device such as an air bag 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 to a preset threshold value and a small or large value. Comparison is performed, and the operation control of the airbag is performed based on the comparison result. This type of acceleration sensor is often mounted on a floor tunnel in a vehicle, and this acceleration sensor is sometimes referred to as a floor acceleration sensor.

  In general, depending on the type of collision, the direction of collision, or the type of object to be collided, the vehicle's collision type can be a full lap collision that collides with the entire front surface, an offset collision that collides front with either the left or right side, and a front pole. It is classified as a center collision.

  Of these, in the case of a full lap collision, the left and right side members of the vehicle receive an impact due to the collision, and thus a great deceleration occurs on the floor tunnel to which the floor acceleration sensor is attached within a predetermined time after the collision. In the case of a collision other than a full wrap collision, since such impact is not received, a large deceleration is not generated on the floor tunnel within a predetermined time after the collision. Therefore, since the floor acceleration sensor is less susceptible to impacts other than full-wrap collisions, it is not preferable to control the operation of an airbag or the like using only one floor acceleration sensor.

  In order to improve this, in Patent Document 1, in order to deal with an offset collision and a center collision, a front acceleration sensor is provided at the front of the vehicle on the right diagonally forward and left diagonally forward with respect to the floor acceleration sensor, in addition to the floor acceleration sensor. When the front acceleration sensor is ON, the operation threshold of the airbag electronic control unit (ECU) is switched to a lower one to operate the airbag.

  FIG. 6 shows a conventional example in which an acceleration sensor is arranged in the front part of the vehicle as in Patent Document 1, (a) is a right offset collision, (b) is a left offset collision, (c) is a center collision, and (d). Indicates the collision mode of full lap collision. FIG. 7 shows the magnitude of acceleration generated by each acceleration sensor in each collision mode shown in FIG. 6, and the main sensor is the main acceleration sensor 6 provided in the airbag electronic control unit (ECU) 1 shown in FIG. It is. As sub-sensors, a right front acceleration sensor 2 provided on the right side of the front portion of the vehicle, a left front acceleration sensor 3 provided on the left side, and a center front acceleration sensor 4 also provided on the center are added. . In addition, a right side acceleration sensor 7 and a left side acceleration sensor 8 are provided as side collision detection devices.

  As shown in FIG. 7, the conditions under which the airbag operates are detected by detecting the acceleration generated by the three sub-sensors, determining the collision mode from the magnitude of the generated acceleration, and changing the determination threshold according to the determined collision mode. However, it is activated only when the acceleration detected from the main acceleration sensor 6 exceeds the determination threshold.

  In recent years, the side acceleration sensors 7 and 8 have been increasingly installed with occupant restraint devices and side acceleration sensors corresponding to side collisions due to stricter regulations on side collisions. This state is shown in FIG.

Japanese Patent Laid-Open No. 10-152014

  By the way, as shown in Patent Document 1, if the front acceleration sensor is disposed in the front part of the vehicle, a plurality of front acceleration sensors and a wire harness for connecting an airbag computer are required, which increases costs. In addition, in the case of a collision mode in which the front portion is greatly deformed, the front acceleration sensor may be broken, or the wire harness may be broken, causing the airbag to be delayed or deactivated.

  In view of the above, an object of the present invention is to provide a frontal collision detection device that can detect a frontal collision using a side acceleration sensor and can reduce costs.

  In order to achieve the above object, according to the present invention, there is provided a frontal collision detection device that detects an impact at the time of a collision by an acceleration sensor, wherein the acceleration sensor is provided behind a front end of a vehicle interior, and the acceleration sensor In addition, a control unit is provided that is disposed in the vicinity of both ends in the vehicle width direction of the vehicle body and between them, and that determines the collision mode of the vehicle based on the difference between the acceleration signals detected from the respective acceleration sensors.

  In order to detect a frontal collision, an acceleration sensor provided behind the front end of the vehicle interior is used, and a plurality of acceleration sensors respectively disposed between and in the vicinity of both ends in the vehicle width direction of the vehicle body are used. If the acceleration sensors at both ends of the vehicle body in the vehicle width direction are side acceleration sensors, and the acceleration sensor therebetween is the main acceleration sensor, the control unit determines the vehicle collision mode based on the difference value of the acceleration signals detected from each acceleration sensor. .

  For example, as shown in FIG. 4, when an acceleration “medium” of the main acceleration sensor, an acceleration “medium” of the right side acceleration sensor, and an acceleration “small” of the left side acceleration sensor are detected, the right offset collision and the collision mode are detected. Is determined. When the acceleration “medium” of the main acceleration sensor, the acceleration “small” of the right side acceleration sensor, and the acceleration “medium” of the left side acceleration sensor are detected, the left offset collision and the collision form are determined. If the acceleration of the main acceleration sensor is “large” or “medium”, the acceleration of the right side acceleration sensor is “medium” or “small”, and the acceleration of the left side acceleration sensor is “medium” or “small”, Determine the collision mode. Further, when the center acceleration “large”, the right acceleration “large”, and the left acceleration “large” are detected, the full-lap collision and the collision form are determined.

  After determining the collision mode, the control unit subsequently changes the operating condition according to the collision mode. For example, in the case of an offset collision or a center collision, the operation condition lowers the determination threshold value of the electronic control unit (ECU) of the occupant restraint device. In the case of a full lap collision, the determination threshold is left as it is. And when the detected acceleration exceeds a threshold value, an occupant restraint device is operated. When the detected acceleration does not exceed the threshold value, the occupant restraint device is not operated.

  As described above, the side acceleration sensor for side collision is used for detecting frontal collision, so the front acceleration sensor and wire harness are not required and the cost can be reduced compared to the case where the front acceleration sensor is arranged at the front of the vehicle. It becomes. In addition, since each acceleration sensor that detects a frontal collision is provided behind the front end of the vehicle interior, it is possible to prevent each acceleration sensor from being damaged during a frontal collision.

  In addition, the detection of the collision mode is not based on the magnitude of the generated acceleration in the front-rear direction of the side acceleration sensor, but the difference value between the acceleration sensors, so the collision mode can be determined even with a small generated acceleration. On the basis of the determination result, the operating condition of the occupant restraint device can be changed to operate the occupant restraint device under the optimum operating condition.

It is a control block diagram of the front collision detection device for a vehicle which is an embodiment of the present invention. The outline | summary of the front collision detection logic circuit for discriminating a collision form using the difference of an acceleration calculation value is shown, (a) is the whole logic circuit, (b) is a logic circuit for right offset collision, (c) is The left offset collision logic circuit, (d) shows the center collision logic circuit. It is explanatory drawing which shows the collision form of a front collision detection apparatus, and arrangement | positioning of the acceleration sensor of a vehicle, (a) is a right side offset collision, (b) is a left side offset collision, (c) is a center collision, (d) is a full wrap. Indicates a collision. It is the figure which represented the magnitude | size of the generated acceleration of each acceleration sensor in each collision form shown in FIG. 3 in a tabular form. It is a control flowchart of a front collision detection device. It is explanatory drawing which shows the collision form of the conventional front collision detection apparatus and arrangement | positioning of the acceleration sensor of a vehicle, (a) is a right side offset collision, (b) is a left side offset collision left, (c) is a center collision, (d ) Indicates a full lap collision. It is the figure which represented the magnitude | size of the generated acceleration of each acceleration sensor in each collision form shown in FIG. 6 in a tabular form.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same functional parts as those shown in FIG. 6 are denoted by the same reference numerals. The vehicle according to the present embodiment is provided with a front collision detection device 10 that detects an impact at the time of front collision by the acceleration sensors 6, 7, and 8. The acceleration sensors 6, 7, and 8 are provided behind the front end of the vehicle interior. The acceleration sensors 6, 7, and 8 are respectively arranged near and between both ends of the vehicle body in the vehicle width direction.

  As the acceleration sensors provided in the vicinity of both ends in the vehicle width direction of the vehicle body, side acceleration sensors 7 and 8 that can detect at least one-axis acceleration in the front-rear direction are employed. In recent years, the mounting rate of occupant restraint devices and side acceleration sensors corresponding to side collisions has increased, so that the side acceleration sensor can be used with a function of detecting longitudinal and lateral acceleration. As the side acceleration sensors 7 and 8, sensors that detect two axes in the front-rear direction and the left-right direction are used. Either a 2-axis integrated acceleration sensor or a separate side acceleration sensor for each axis may be used. Further, even a uniaxial detection-type side acceleration sensor can be mounted on a vehicle body frame or the like at an angle (for example, 45 degrees) that can detect the front-rear and left-right directions with one axis.

  The side acceleration sensors 7 and 8 are disposed on a body frame that propagates an impact at the time of a frontal collision of the vehicle or a portion that is joined to the body frame. Regardless of the type of collision, the frontal collision is impacted by the two left and right side members of the vehicle body frame, so the side acceleration sensors 7 and 8 are arranged on the left and right side members of the vehicle body frame, or this Although it is desirable to arrange at the center pillar (B pillar) joined to the vehicle body frame, it may be arranged at the front pillar (A pillar), rear pillar (C pillar), and other pillars. Further, the side acceleration sensors 7 and 8 may be arranged at the front door portion or the rear door portion. The left and right side acceleration sensors 7 and 8 are preferably located at the same position in the front-rear direction of the vehicle, but may be arranged in a state shifted in the front-rear direction. In the case of a side acceleration sensor displaced in the front-rear direction, the acceleration detected according to the front-rear positional relationship can be corrected.

  The side acceleration sensors 7 and 8 of this type also function as a safing sensor at the time of a frontal collision, whereby the safing sensor mounted on the electronic control unit (ECU) 1 of the airbag can be eliminated.

  The acceleration sensor disposed between the two side acceleration sensors 7 and 8 in the vehicle width direction of the vehicle body is the main acceleration sensor 6. As the main acceleration sensor 6, an acceleration sensor mounted on an electronic control unit (ECU) 1 for an airbag can be used. The main acceleration sensor 6 is usually disposed in front of a floor tunnel in the vehicle interior. The main acceleration sensor 6 is preferably integrated with the electronic control unit (ECU) 1 of the airbag 14, but is not limited thereto, and may be provided separately. As shown in FIG. 3, the main acceleration sensor 6 is disposed in front of the side acceleration sensors 7 and 8, but is not limited thereto, and the main acceleration sensor 6 and the side acceleration sensors 7 and 8 An aspect in which the main acceleration sensor 6 is arranged behind the side acceleration sensors 7 and 8 may be adopted.

  The front collision detection device 10 is provided with a control unit 13 that determines a vehicle collision mode based on a difference between acceleration signals detected from the acceleration sensors 6, 7, and 8. The control unit 13 can use an electronic control unit (ECU) 1 such as an airbag 14. The control unit 13 includes a collision type determination unit 15 that determines a vehicle collision type based on at least a difference in acceleration detected from each of the acceleration sensors 6, 7, and 8. Further, the control unit 13 determines whether or not to change the operating condition of the airbag 14 or the like based on the determination result by the collision mode determining unit 15, and a change command for the operating condition changing unit 16. And an operation determination means 17 for comparing the detected acceleration with the operation condition based on the operation condition changed based on the above and determining whether or not the occupant restraint device 14 such as an air bag should be operated.

For example, as shown in FIG. 3, the collision type discrimination means 15 is a right-side offset collision as shown in FIG. 3A, a left-side offset collision as shown in FIG. ) And a full lap collision as shown in FIG. For example, in the case of the right offset collision in FIG. 5A, the acceleration (or deceleration, the same applies hereinafter) from the main acceleration sensor 6 is “middle”, the right side acceleration sensor 7 is “middle”, and the left side acceleration sensor 8 is. When an acceleration signal of “small” is input, the offset collision on the right side is determined based on the difference.
Similarly, in the case of the left offset collision in FIG. 5B, for example, a signal “middle” from the main acceleration sensor 6, a “small” signal from the right side acceleration sensor 7, and a “middle” signal from the left side acceleration sensor 8 are output. When input, it is determined as an offset collision on the left side based on the difference value.
Further, in the case of the center collision shown in FIG. 5C, for example, when “large or medium” signals are input from the main acceleration sensor 6 and “medium or small” signals are input from the both side acceleration sensors 7 and 8, the difference is calculated. Based on this, a center collision is determined.
Further, in the case of the full lap collision shown in FIG. 4D, when acceleration signals having the same magnitude are input from the main acceleration sensor 6 and the both side acceleration sensors 7 and 8, it is determined that a full lap collision has occurred.

  The discrimination result of the collision mode discrimination means 15 is input to the operating condition change means 16. The operating condition changing means 16 changes the operating condition according to the collision mode (including the case where it is maintained). For example, in the case of an offset collision or a center collision, the determination threshold value for operating the occupant restraint device 14 is decreased by a predetermined amount. A threshold value (predetermined amount) to be lowered is set for each of the offset collision and the center collision. In the case of a full lap collision, the determination threshold value for operating the occupant restraint device 14 is maintained as it is.

  The operation determining means 17 determines whether or not the acceleration for operating the occupant restraint device 14 has been reached based on the changed or maintained determination threshold. In this case, it is determined whether or not the acceleration input from the main acceleration sensor 6 exceeds the determination threshold. If the acceleration exceeds the determination threshold, the occupant restraint device 14 is operated. The occupant restraint device 14 is deactivated.

  In addition, although the example which changes the determination threshold value as mentioned above in the operating condition change means 16 was shown, not only this but the determination threshold value is maintained and the acceleration input from the main acceleration sensor 6 is multiplied by a predetermined rate. Thus, it is also possible to employ a technique in which the amplification is an operation condition changing means.

  FIG. 2 shows an outline of a frontal collision detection logic circuit that is a logic circuit of the control unit 13 and that determines a collision mode using a difference between acceleration calculation values. FIG. 4A shows the entire logic circuit. The input circuit from the main acceleration sensor 6, the logic circuit for the right offset collision, the logic circuit for the left offset collision, the logic circuit for the center collision, and the logic circuit from the safing sensor. The circuit configuration is such that the frontal collision occupant restraint device 14 is operated based on the input circuit.

  FIG. 2B is a logic circuit for a right offset collision, and outputs an H signal if the difference in acceleration from the right side acceleration sensor 7 and the left side acceleration sensor 8 is a predetermined amount (α). The circuit configuration is such that an ON signal is output under an AND condition with the acceleration signal from the acceleration sensor 6 (see FIG. 5A), and the collision mode of the right offset collision is determined.

  FIG. 2 (c) is a logic circuit for left offset collision, which outputs an H signal if the difference in acceleration from the left side acceleration sensor 8 and the right side acceleration sensor 7 is a predetermined amount (β). The circuit configuration is such that an ON signal is output under an AND condition with the acceleration signal from the acceleration sensor 6 (see (a) in the figure) to determine the collision mode of the left offset collision.

  FIG. 2D is a logic circuit for center collision, and the upper two logic circuits are NOT circuits, and the difference in acceleration from the left and right side acceleration sensors 7 and 8 is less than a predetermined amount (α) (β). The lower two-stage logic circuit outputs an H signal if the difference in acceleration between the main acceleration sensor 6 and the left and right side acceleration sensors 7, 8 is greater than or equal to a predetermined amount (γ) (δ), and the AND condition of these The H signal is output, and the ON signal is output under an AND condition with the acceleration signal from the main acceleration sensor 6 (see (a) in the figure) to determine the collision mode of the center collision.

  The occupant restraint device 14 can be exemplified by an airbag device, a seat belt device with a pretensioner, and the like, and the occupant restraint device 14 is actuated via a drive circuit (not shown) by an ON signal from the operation discriminating means 17 of the control unit 13. . In this embodiment, an airbag apparatus is illustrated.

  Control of the front collision detection apparatus 10 in this embodiment will be described based on the flowchart of FIG. In the front collision detection device 10, constant acceleration signals are input to the control unit 13 from the side acceleration sensors 7 and 8 and the central main acceleration sensor 6. First, the control unit 13 determines whether or not the generated acceleration of the right side acceleration sensor 7 is larger by a predetermined amount than the generated acceleration of the left side acceleration sensor 8 (S1). That is, the difference between the generated accelerations from both side acceleration sensors 7 and 8 is calculated, and it is determined whether or not the difference is equal to or greater than a predetermined amount (α). When the difference between the generated acceleration on the right side and the generated acceleration on the left side is larger by a predetermined amount (α), the collision form determining unit 15 determines that the collision is a right offset collision, and the operating condition changing unit 16 determines that the operation condition changing unit 16 is in accordance with the determination result. Is lowered by a predetermined amount. The operation determination means 17 determines whether or not to operate the occupant restraint device 14 by comparing with the acceleration detected from the main acceleration sensor 6 based on the decreased determination threshold (S2).

  When the acceleration from the right side acceleration sensor 7 does not reach a predetermined amount with respect to the acceleration generated by the left side acceleration sensor 8 (S1: NO), the collision type discrimination means 15 then performs the left side acceleration sensor. It is determined whether the generated acceleration 8 is larger than the generated acceleration of the right side acceleration sensor 7 by a predetermined amount (S3). When the difference between the generated acceleration on the left side and the generated acceleration on the right side is larger than a predetermined amount (β), the collision form determining unit 15 determines that the collision is the left offset collision. The operating condition changing means 16 reduces the operation determination threshold value of the occupant restraint device 14 by a predetermined amount based on the determination result. The operation discriminating means 17 determines whether or not to operate the occupant restraint device 14 after comparing with the acceleration detected from the main acceleration sensor 6 based on the lowered determination threshold value (S4).

  In the collision form discrimination means 15, when the acceleration generated by the left side acceleration sensor 8 does not reach a predetermined amount as compared with the acceleration generated by the right side acceleration sensor 7 (S3: NO), the generation of the main acceleration sensor 6 is performed. It is determined whether the acceleration is larger by a predetermined amount than the acceleration generated by the left and right side acceleration sensors 7, 8 (S5). When the difference between the generated acceleration of the main acceleration sensor 6 and the left and right generated accelerations is larger than a predetermined amount, the collision form determining unit 15 determines that the collision is a center collision. The operating condition changing means 16 reduces the operation determination threshold value of the occupant restraint device 14 by a predetermined amount based on the determination result. The operation determination means 17 determines whether or not to operate the occupant restraint device 14 based on the decreased determination threshold value (S6).

  Further, the collision form determination means 15 determines that it is a full lap collision when the generated accelerations of the left and right side acceleration sensors 7, 8 and the main acceleration sensor 6 are the same (S7: NO). The operation condition changing means 16 leaves the operation determination threshold value of the occupant restraint device 14 based on the determination result. The operation determination means 17 determines whether or not to operate the occupant restraint device 14 based on the determination threshold (S8).

  As described above, in the present embodiment, the side collision side acceleration sensors 7 and 8 can be used for frontal collision detection, and can also be used as a side collision acceleration sensor, so that the cost can be reduced. Further, the feature amount detected in the collision mode is determined not by the magnitude of the generated acceleration in the front-rear direction of the side acceleration sensors 7 and 8 but by the difference value between the acceleration sensors. This is one of the characteristic configurations.

In the front collision detection device, as shown in Patent Document 1, an acceleration sensor that is sub to the main acceleration sensor is basically arranged at a position close to the collision object so that the generated acceleration at the time of collision is large. There is a way of thinking. In particular, in medium-sized vehicles and large-sized vehicles, the front portion is mainly used for the acceleration of offset collision and center collision, and the acceleration of the collision cannot be detected with an acceleration sensor mounted in the passenger compartment, or detection is delayed.
On the other hand, in minicars and small cars, vehicle rotation and vehicle deformation during offset collision and center collision are large, and the acceleration generated by the acceleration sensor mounted in the passenger compartment can be detected greatly. Therefore, this type of mini vehicle or small vehicle is effective because the acceleration sensor 6, 7 and 8 mounted in the passenger compartment can sufficiently determine the front collision type.

  Moreover, in general, the acceleration sensor is used to detect the magnitude of the generated acceleration at the time of collision, but in this embodiment, the difference between the generated accelerations of the plurality of acceleration sensors 6, 7, and 8 is used. Therefore, in a light vehicle or a small vehicle in which the difference is large and the vehicle rotation or vehicle deformation is large, it can be used as a particularly effective collision mode discrimination means.

  As described in the above embodiment, the side acceleration sensor for side collision is used for detecting frontal collision. Therefore, the front acceleration sensor and the wire harness are compared with the case where the front acceleration sensor is arranged in the front part of the vehicle. It becomes unnecessary and can reduce the cost. In addition, since each acceleration sensor that detects a frontal collision is provided behind the front end of the vehicle interior, it is possible to prevent each acceleration sensor from being damaged during a frontal collision.

  In addition, because the detection of the collision mode is not based on the magnitude of the generated acceleration in the front-rear direction of the side acceleration sensor, but the difference between each acceleration sensor, the collision mode can be determined even with a small generated acceleration. Based on the determination result, the operating condition of the occupant restraint device can be changed to operate the occupant restraint device under the optimum operating condition.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added within the scope of the present invention. For example, the main acceleration sensor is not limited to that attached to the floor tunnel located at the center in the vehicle width direction of the vehicle body as in the above embodiment, and the attachment position is particularly limited as long as it is between both side acceleration sensors. It is not something.

1 Airbag electronic control unit (ECU)
2 Right Front Acceleration Sensor 3 Left Front Acceleration Sensor 4 Center Front Acceleration Sensor 6 Main Acceleration Sensor 7 Right Side Acceleration Sensor 8 Left Side Acceleration Sensor 10 Front Collision Detection Device 13 Control Unit 14 Crew Restraint Device 15 such as an Airbag Collision Mode Discriminating means 16 Operating condition changing means 17 Operating discriminating means

Claims (2)

A front collision detection device for a vehicle that detects an impact at the time of collision by an acceleration sensor,
The acceleration sensor is provided behind the front end of the vehicle interior,
The acceleration sensor is disposed near and between both ends in the vehicle width direction of the vehicle body,
A front collision detection apparatus for a vehicle, comprising a control unit that determines a vehicle collision mode based on a difference in acceleration signals detected from each acceleration sensor. The vehicle front collision detection device according to claim 1, wherein the acceleration sensors near both ends of the vehicle body in the vehicle width direction are arranged on a vehicle body frame that propagates an impact at the time of a frontal collision or a portion joined to the vehicle body frame.

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