JP4736740B2 - Vehicle collision detection system - Google Patents

Description

  The present invention relates to a vehicle collision detection system that detects a vehicle collision, and more particularly, to a vehicle collision detection system that does not cause false detection even when a pressure fluctuation (change in atmospheric pressure, etc.) occurs around the vehicle.

  The vehicle is provided with an occupant protection system that protects the occupant during a collision. The occupant protection system includes, for example, an airbag that is deployed at the time of collision to protect the occupant. In recent years, there is a demand not only for the impact in the longitudinal direction of the vehicle but also for the protection of the occupant against a collision in the lateral direction (the width direction of the vehicle). Due to such demands, side airbags and curtain airbags have been mounted. An occupant protection system including an airbag includes a collision detection system that detects a collision with a vehicle, and an occupant protection device (airbag) that operates when the collision detection system detects a collision to protect the occupant. Is done.

  A conventional collision detection system for a collision from the side of a vehicle is disclosed in Patent Document 1, for example. The collision detection system disclosed in Patent Document 1 is a system including a hollow body disposed on a side surface portion of a vehicle body and at least one detector that responds to a pressure increase in the hollow body, and the hollow body is crushed by the collision. The detector detects the pressure increase in the hollow body. The collision is determined when the gradient of the pressure fluctuation in the hollow body or the amplitude of the pressure fluctuation exceeds a predetermined value.

However, such a collision detection system has a problem that an appropriate collision cannot be detected due to the influence of atmospheric pressure. Specifically, the hollow body whose pressure changes due to the collision is not a completely closed hollow body, but is formed to have air permeability between the inside and the outside of the hollow body. This air permeability is formed so that the internal pressure sufficiently fluctuates when the hollow body is deformed by a collision. In a collision when a vehicle equipped with this collision detection system travels at a high altitude or the like at a high altitude, the atmospheric pressure is low, so the amount of fluctuation in pressure in the hollow body due to the collision is small. In the conventional system, since the pressure fluctuation amount is compared with the threshold value and determined to be a collision, if the pressure fluctuation amount in the hollow body due to the collision is small, the collision may not be determined. . If the collision detection system cannot determine that there is a collision, the occupant protection device of the occupant protection system does not operate, and there is a problem that the occupant cannot be protected.
Japanese Patent No. 2654428

  This invention is made | formed in view of the said actual condition, and makes it a subject to provide the collision detection system which can determine a collision correctly irrespective of the surrounding condition.

  In order to solve the above-mentioned problems, the present inventor has studied the collision detection system, and as a result, has come to make the present invention.

A collision detection system according to the present invention is a vehicle collision detection system that is mounted on a vehicle and detects a collision of the vehicle. A vehicle body member in which a predetermined space is formed and the space is deformed by the collision; A pressure detection means for detecting pressure, and a collision determination means for determining a collision based on the pressure detected by the pressure detection means, the pressure detection means measures the pressure in the space at least three times , The collision determination means is the pressure in the space detected by the pressure detection means, the new pressure in the space at the latest time, and the pressure in the plurality of spaces measured by the pressure detection means multiple times before the newest time . From the ratio of the average pressure to the old pressure, the volume change rate, which is the change rate of the volume of the space, is obtained.

The collision detection system of this invention is a system which detects a collision from the change of the volume of the space which arises when the space divided by the vehicle body member deform | transforms. In other words, since the collision is not detected from the change in the pressure in the space, an error in the detection result due to the external pressure does not occur.

In addition, since the collision detection system of the present invention is a system that detects a collision based on a change in the volume of the space that is generated when the space defined by the vehicle body member is deformed, various collisions can be made by setting the location of the vehicle body member. Can be detected.

In the collision detection system of the present invention , the pressure detection unit measures the pressure in the space at least three times, and the old pressure is measured in a plurality of spaces measured by the pressure detection unit a plurality of times before the new pressure is detected. The average pressure of the internal pressure. By using the old pressure as the average pressure measured over a plurality of times, the volume change rate in the space can be obtained when the pressure in the space is measured twice or more.

The collision detection system according to claim 2 , wherein the pressure detection means repeatedly measures the pressure in the space every predetermined time, and the collision determination means performs the collision based on the pressure in the space repeatedly measured a predetermined number of times. Judgment is made. By measuring the pressure in the space every predetermined time, even if the external environment changes rapidly, the change in the environment can be detected, and this change can be reflected in the old pressure.

In the collision detection system according to the third aspect , the vehicle body member is a vehicle door. The vehicle door is disposed on the outer periphery of the vehicle, and is deformed at the time of a collision from the side. That is, by using the vehicle door as a vehicle body member, a collision is detected from a change in the volume inside the vehicle door, and the collision detection system of the present invention is an effective system for detecting a side collision of the vehicle. It becomes.

In the collision detection system according to the fourth aspect , the pressure detection means is disposed on the door inner panel of the vehicle door, and the space is a space inside the door of the vehicle door. A typical vehicle door includes an outer panel that forms a part of the outer peripheral surface of the vehicle and an inner panel that forms a surface of the vehicle door on the vehicle interior side. A space in the door between the inner panel and the outer panel can be a space for measuring pressure. That is, since it is not necessary to provide a vehicle body member having a space in which the internal pressure is newly measured, an increase in cost required for the collision detection system of the present invention can be suppressed.
The collision detection system according to claim 5 , wherein the pressure detection means continuously repeats the measurement of the pressure in the space, and the new pressure determines the old pressure or the average pressure when the next new pressure is measured. One of the multiple pressures.

  The collision detection means of the present invention is a system that detects a collision from a change in the volume of the space that occurs when the space defined by the vehicle body member is deformed. In other words, since the collision is not detected from the change in the pressure in the space, an error in the detection result due to the external pressure does not occur.

  Hereinafter, the collision detection system of the present invention will be described in more detail using examples.

Example 1
The collision detection system of the present embodiment is a system whose configuration is shown in FIGS. The collision detection system of the present embodiment is a system having a pressure sensor 1 and a collision determination ECU 2.

  The pressure sensor 1 is not particularly limited as long as it is a sensor capable of measuring pressure. For example, a pressure sensor similar to the pressure sensor used in the conventional collision detection system can be used.

  As shown in FIG. 2, the pressure sensor 1 is assembled to the door 3 on the right side of the vehicle. The vehicle door 3 includes an outer panel 30 that forms a part of the outer peripheral surface of the vehicle, an inner panel 31 that forms a surface of the vehicle door 3 on the vehicle interior side, and a window glass 32. A substantially sealed space is formed between the outer panel 30 and the inner panel 31. The substantially sealed space 33 is formed so that the inside and outside of the door 3 are slightly connected to each other. When the pressure outside the door 3 changes, the pressure in the space 33 inside the door 3 also changes. When the internal volume of the space 33 changes rapidly, the internal pressure is increased.

  First, when an object collides with the door 3 of the vehicle, the object contacts the outer panel 30 and presses the outer panel 30 in the in-vehicle direction. By this pressing, the outer panel 30 is deformed so as to protrude toward the inner panel 31. Since the inner panel 31 is not subjected to direct collision stress, its shape is maintained. As a result, when the outer panel 30 is deformed, the volume of the space 33 in the door 3 is rapidly reduced. When the volume of the space 33 decreases rapidly, the pressure in the space 33 increases. As described above, the space 33 communicates with the outside of the door 3, but the pressure in the space 33 rises because it is formed so as not to follow a sudden change in internal pressure. The pressure in the space 33 is measured by the pressure sensor 1.

  The collision determination ECU 2 receives the detection result (detection signal) of the pressure in the space 33 by the pressure sensor 1 and determines a collision from the detection signal. In the collision determination ECU 2, the volume change rate of the space 33 is obtained from the pressure of the space 33 before and after the collision, and the collision is determined from the volume change rate.

  Specifically, in the door 3 of the vehicle, the airtightness of the space 33 is ensured by an inner wall and a drip-proof sheet (not shown). For this reason, Boyle's law is dynamically established in the space 33. For this reason, the change rate of the volume of the space 33 can be obtained from the pressure before and after the collision.

_Assuming that the pressure in the space 33 _before the collision is P _before , the pressure _after the collision is P _after , the volume _before the collision is V _before , and the amount of change in the volume of the space 33 due to the collision is ΔV, It holds.

  When formula 1 is transformed, the following formula 2 is obtained.

Here, V _before can be measured in advance because it is the volume of the space 33 before the collision. That is, the amount of change (ΔV) in the volume of the space 33 due to the collision can be obtained from the pressure before and after the collision.

In the collision detection system of this embodiment, the pressure in the space 33 is measured by the pressure sensor 1 every predetermined time. Then, the collision determination ECU 2 determines the collision based on the latest five measurement results among the pressures in the space 33 measured by the pressure sensor 1. The number of times the pressure is measured is a set value in the present embodiment, and may be an arbitrary set value in the collision detection system of the present embodiment. Specifically, among the latest five measurement results, the most recent one measurement result is defined as P _after , the average of the old four measurement results is obtained, and this average is _defined as P _before . Then, the change amount (ΔV) of the space 33 is obtained by using the above-described equation 2 together with the measured V _before . Then, a change rate of the volume of the space 33 is obtained from the calculated change amount, and when this change rate exceeds a preset threshold value, it is determined as a collision.

(Collision detection)
More specifically, detection of a collision in the collision detection system of the present embodiment will be described.

  In the collision detection system of this embodiment, the pressure in the space 33 is measured by the pressure sensor 1 every predetermined time. Let Pn be the pressure measured at time (Tn).

  The pressure measurement was repeated with the pressure sensor 1, and the collision determination ECU 2 was input up to the pressure Pn measured at time Tn, the pressure Pn + 1 measured at time Tn + 1, and the pressure Pn + 4 measured at time Tn + 4.

In the collision determination ECU 2, we obtain an average of the input Pn~Pn + 3, to the average and P _before. Further, the amount of change (ΔV) of the space 33 is obtained using the above equation 2 with Pn + 4 as P _after . Then, a change rate of the volume of the space 33 is obtained from the calculated change amount, and when the change rate exceeds a preset threshold value, it is determined that a collision has occurred at time (Tn + 4). Here, since the airtightness of the door 3 of the vehicle is different for each vehicle, the change rate threshold value cannot be determined unconditionally.

Subsequently, when a predetermined time elapses from time Tn + 4 and reaches time Tn + 5, the pressure sensor 1 measures the pressure Pn + 5. Then, an average of Pn + 1~Pn + 4, the mean and P _before, a determination of a collision in the same manner as described above to Pn + 5 as _{P after.}

  As described above, the space 33 communicates with the outside of the vehicle, and the pressure in the space 33 before the collision is the atmospheric pressure outside the vehicle. And since the collision detection system of a present Example calculates | requires the change rate of the volume of the space 33 and determines a collision from this change rate, it is not received by the atmospheric pressure outside a vehicle. That is, even when the vehicle travels on a high altitude with low atmospheric pressure, it is possible to detect a collision.

  As shown in FIG. 1, the collision detection system according to the present embodiment can be used for a collision detection system in a protection system against a side collision of a vehicle such as a side airbag system or a curtain airbag system. In these protection systems, when the collision detection system determines a collision, the determination result is input to the airbag deployment control ECU 4, and the airbag deployment control ECU 4 instructs to deploy the side airbag 50 and the curtain airbag 51. To do. In response to an instruction from the airbag deployment control ECU 4, the airbags 50 and 51 are deployed, and a passenger is prevented from colliding with the side surface of the vehicle.

(Other forms of Example 1)
The collision detection system of the first embodiment is a system in which the pressure sensor 1 is assembled only to the right door 3 of the vehicle. However, as shown in FIG. 3, the pressure sensor 1 ′ may be assembled to the left door. Good. In the collision detection system shown in FIG. 3, the left collision can be detected from the pressure in the space inside the left door in the same manner as in the first embodiment.

  Even in this modified embodiment, as in the case of the first embodiment, the effect of detecting a collision without depending on the external atmospheric pressure is exhibited.

( Reference example )
The collision detection system of this reference example is a system whose configuration is shown in FIG. The collision detection system of this reference example is a system having a pressure sensor 10 assembled to the right door 3, a pressure sensor 11 assembled to the left door, and a collision determination ECU 2.

  The pressure sensors 10 and 11 are not particularly limited as long as they can measure pressure. For example, a pressure sensor similar to the pressure sensor used in the conventional collision detection system can be used.

  The pressure sensor 10 is assembled to a door on the right side of the vehicle. The pressure sensor 11 is assembled to the left door of the vehicle. The vehicle door to which the pressure sensors 10, 11 are assembled has the same configuration except that it is formed to be symmetrical. The vehicle door includes an outer panel that forms part of the outer peripheral surface of the vehicle, an inner panel that forms a surface of the vehicle door on the vehicle interior side, and a window glass. A substantially sealed space is formed between the outer panel and the inner panel. This substantially sealed space is formed by slightly communicating the inside and outside of the door. When the pressure outside the door changes, the pressure in the space inside the door also changes, and the volume of this space increases. When the pressure changes suddenly, the internal pressure is increased.

  The collision determination ECU 2 receives the detection result (detection signal) of the space pressure by the pressure sensors 10 and 11 and determines a collision from the detection signal. The collision determination ECU 2 obtains the change rate of the volume of the space from the pressure in the space before and after the collision, and determines the collision from the change rate of the volume.

The collision detection system of this reference example is a system that detects a collision using P _before in the collision detection system of the first embodiment as the pressure of the door on the side where no collision occurs. For example, when a collision occurs on the right door, the pressure on the right door becomes P _{after and} the pressure on the left door becomes P _before . Then, the collision determination ECU 2 determines the collision in the same manner as in the first embodiment.

The collision detection system of this reference example can be used for the collision detection system in the protection system as in the first embodiment. These protection systems prevent the occupant from colliding with the side surface of the vehicle by deploying the side airbag or the curtain airbag when the collision detection system determines that the collision has occurred.

Similarly to the collision detection system of the first embodiment, the collision detection system of this reference example is a system that is not affected by atmospheric pressure outside the vehicle. In other words, the collision can be detected even when the vehicle is traveling on a high altitude with a low atmospheric pressure.

It is the figure which showed the structure of the collision detection system of Example 1. FIG. It is the figure which showed the structure of the vehicle door vicinity of the collision detection system of Example 1. FIG. It is the figure which showed the structure of the deformation | transformation form of the collision detection system of Example 1. FIG. It is the figure which showed the structure of the collision detection system of a reference example .

Explanation of symbols

1, 10, 11: Pressure sensor 2: Collision judging ECU
3: Vehicle door 30: Outer panel 31: Inner panel 32: Wind glass 33: Space 4: ECU for airbag deployment control
50: Side airbag 51: Curtain airbag

Claims (5)

A vehicle collision detection system that is mounted on a vehicle and detects a collision of the vehicle,
A vehicle body member in which a predetermined space is formed and the space is deformed by the collision;
Pressure detecting means for detecting the pressure in the space;
A collision determination means for determining a collision based on the pressure detected by the pressure detection means;
Have
The pressure sensing means measures the pressure in the space at least three times ;
The collision determination means is the pressure in the space detected by the pressure detection means, the new pressure in the space at the latest time, and the pressure detection means measured a plurality of times before the newest time. A vehicle collision detection system, wherein a volume change rate, which is a change rate of the volume of the space, is obtained from a ratio of the average pressure of the plurality of pressures in the space to an old pressure. The pressure detection means repeatedly measures the pressure in the space every predetermined time,
The vehicle collision detection system according to claim 1 , wherein the collision determination unit determines a collision based on a pressure in the space repeatedly measured a predetermined number of times. The vehicle collision detection system according to claim 1 , wherein the vehicle body member is a vehicle door. The pressure detecting means is disposed on a door inner panel of the vehicle door,
The vehicle collision detection system according to claim 1 , wherein the space is a space inside the door of the vehicle door. The pressure detection means continuously repeats the measurement of the pressure in the space,
The vehicle collision detection system according to claim 1 , wherein the new pressure is one of a plurality of pressures for determining the old pressure or the average pressure when a next new pressure is measured.

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